CMC · California Mechanical Code
What are the support, access, illumination and service-receptacle requirements for refrigeration equipment?
Homeowners: refrigeration equipment must sit on an approved base (ground units raised at least 3 inches), be reachable through an unobstructed service opening (normally 36" × 80"), have permanent lighting controlled at the access point, and have a 120 V outlet within 25 feet for maintenance — these requirements are in **§ 1105.2**, **§ 1105.3**, and **§ 1105.4** of the California Mechanical Code.
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
The California Mechanical Code requires that refrigeration equipment be properly supported/anchored, provided with unobstructed access for routine servicing, equipped with permanent illumination controlled at the access entrance, and have a 120 V service receptacle available for maintenance. The controlling sections are § 1105.2, § 1105.3, and § 1105.4 (with cross-reference to § 301.4 for the receptacle).
The single most important rule: refrigeration equipment that requires routine maintenance must be supported on an approved base, reachable through an unobstructed access opening sized for service, and provided with permanent lighting controlled at that entrance and a nearby 120 V receptacle.
Requirements in detail
Supports and anchorage — key rule
- A compressor or portion of a condensing unit supported from the ground must rest on a concrete or other approved base extending not less than 3 inches (76 mm) above the adjoining ground level. § 1105.2.
Access — key rule
Provide an unobstructed, readily accessible opening and passageway not less than 36 inches (914 mm) wide and 80 inches (2032 mm) high to compressors, required valves, or other portions of the system that require routine maintenance. § 1105.3.
Important exceptions in § 1105.3 allow reduced access dimensions for certain items and locations (see Exceptions & special cases below).
Illumination and service receptacles — key rule
Install permanent luminaires where equipment is required to be accessible or readily accessible. The luminaires must provide sufficient light to perform the required tasks, and control of the illumination must be provided at the access entrance. § 1105.4.
Section 301.4 requires a 120 volt receptacle located within 25 feet (7620 mm) of equipment for service and maintenance; the receptacle must be on the supply side of the disconnect switch. (§ 301.4 is the cross-reference cited by § 1105.4.)
Quick-reference table (decision-relevant dimensions/values)
| Item | Required dimension / condition | Code Reference |
|---|---|---|
| Ground-supported compressor base elevation | ≥ 3 in (76 mm) above adjoining ground | § 1105.2 |
| Standard access opening and passageway | ≥ 36 in (914 mm) wide and ≥ 80 in (2032 mm) high | § 1105.3 |
| Reduced access for certain service items | Unobstructed space ≥ 30 in (762 mm) depth, width, height; where adjacent opening and serviceability allow, opening may be 22 in × 30 in (559 mm × 762 mm) | § 1105.3 (Exceptions) |
| Attic / furred-space equipment access | Minimum opening and passageway 22 in × 30 in (559 mm × 762 mm) permitted for Group A1 or brine equipment | § 1105.3 (Exception) |
| Permanent luminaires | Required for equipment required to be (readily) accessible; control at access entrance | § 1105.4 |
| Exception to luminaires | May omit where fixed building lighting provides required illumination; also equipment on roof/exterior walls | § 1105.4 (Exceptions) |
| Service receptacle | 120 V receptacle within 25 ft (7620 mm); outlet on supply side of disconnect | § 301.4 (cross-referenced by § 1105.4) |
Exceptions & special cases
Portable access allowed for suspended evaporators. Suspended-overhead refrigerant evaporators may use portable means of access instead of the fixed 36" × 80" requirement. § 1105.3.
Smaller clearances for specific components. Air filters, brine control/stop valves, fan motors/drives, and remotely de-energized electrical connections may be provided access to an unobstructed space not less than 30" (762 mm) in depth, width, and height; if the opening is immediately adjacent and equipment can be serviced/replaced through it, the opening may be reduced to 22" × 30" (559 mm × 762 mm). § 1105.3 (Exceptions).
Attic and roof locations. Cooling equipment using Group A1 refrigerants or brine in attics/furred spaces may use a 22" × 30" opening; equipment on roofs/exterior walls may follow furnace-access rules in Section 304.3. § 1105.3 (Exceptions).
Lighting exceptions. Permanent luminaires may be omitted where existing fixed building lighting already provides required illumination, and luminaires are not required for equipment located on roofs or building exterior walls. § 1105.4 (Exceptions).
If you need to rely on a reduced opening or alternate access method, make sure the specific exception language applies to the equipment type and refrigerant group cited in the code.
Common mistakes
- Treating "readily accessible" as "conveniently accessible" — the code requires unobstructed passageway and minimum dimensions unless a stated exception applies. § 1105.3.
- Installing the service receptacle on the load side of the disconnect rather than the supply side (it must be on the supply side per § 301.4).
- Not providing a permanent luminaire controlled at the entrance even when equipment is located in an enclosed space — remember § 1105.4 requires control at the access entrance.
- Failing to raise ground-mounted compressors at least 3 inches above adjoining grade. § 1105.2.
Worked example — concrete scenario
Scenario: A small supermarket installs a ground-mounted condensing unit outdoors beside the building. The unit contains serviceable compressors and valves and will be routinely maintained.
What you must provide (by code):
- Support: Set the compressor on a concrete base that extends at least 3 in (76 mm) above the adjacent ground. § 1105.2.
- Access: Provide an unobstructed service route to the compressor/valves of at least 36 in (914 mm) wide and 80 in (2032 mm) high from the nearest access point so technicians can carry tools and parts through. § 1105.3.
- If the unit is on a roof or along an exterior wall and meets furnace-access conditions, alternative access per § 1105.3 Exception (4) may apply — check Section 304.3.
- Illumination: Install permanent luminaires inside the service space that provide task-level lighting; the light control must be located at the access entrance. § 1105.4.
- Receptacle: Provide a 120 V receptacle within 25 ft (7620 mm) of the equipment for service use, and install it on the supply side of the disconnect. § 301.4 (cross-referenced by § 1105.4).
If any of these requirements are reduced under an exception (for example, portable access for suspended evaporators), confirm that the exception language specifically matches your installation before relying on it.
Related provisions
- § 301.4 — Electrical connections and 120 V receptacle within 25 ft for equipment (cross-referenced by § 1105.4).
- § 1105.5 — Ventilation of rooms containing condensing units (applies when units are inside rooms, linked to access/illumination considerations).
- § 1105.11 — Refrigerant port protection (storage and handling adjacent to service activities).
- § 1106.0 – § 1106.11 — Refrigeration machinery room requirements (when machinery room conditions apply, e.g., for larger systems and flammable refrigerants).
- § 1110.4 — Access for valves and components (see Chapter 11 valve access requirements that can affect service clearances).
Code references
Grounded in the retrieved California Mechanical Code — click a citation to read the verbatim passage:
CMC § 1105.0 High relevance — show source text
1105.0 General Requirements . . . . . . . . . 231
1105.1 Human Comfort . . . . . . . . . . . . . . 231
1105.2 Supports and Anchorage . . . . . . . 231
1105.3 Access . . . . . . . . . . . . . . . . . . . . . 231
1105.4 Illumination and Service
Receptacles . . . . . . . . . . . . . . . . . 231
1105.5 Ventilation of Rooms
Containing Condensing Units . . . . 231
1105.6 Prohibited Locations . . . . . . . . . . . 232
1105.7 Condensate . . . . . . . . . . . . . . . . . 232
1105.8 Defrost . . . . . . . . . . . . . . . . . . . . . 232
1105.9 Overflows . . . . . . . . . . . . . . . . . . . 232
1105.10 Condensate, Defrost, and Overflow Disposal. . . . . . . . . . . . . 232
1105.11 Refrigerant Port Protection . . . . . . 232
1105.12 Storage . . . . . . . . . . . . . . . . . . . . . 232
1106.0 Refrigeration Machinery Rooms . . 232
1106.1 Where Required . . . . . . . . . . . . . . 232
1106.2 Refrigeration Machinery Room, General Requirements . . . . . . . . . 232
1106.3 Normal Operation . . . . . . . . . . . . . 233
1106.4 Natural Ventilation . . . . . . . . . . . . 234
1106.5 Combustion Air . . . . . . . . . . . . . . . 234
1106.6 Ventilation Intake . . . . . . . . . . . . . 234
1106.7 Maximum Temperature . . . . . . . . 234
1106.8 Refrigerant Parts in Air Duct. . . . . 234
1106.9 Dimensions. . . . . . . . . . . . . . . . . . 234
1106.10 Exits . . . . . . . . . . . . . . . . . . . . . . . 234
1106.11 Machinery Room, A2L and B2L . . 234
Table 1106.11.10.2 Refrigerant Detector Set Points, Response Times, Alarms, and Ventilation Levels . . . . . . . . . . . . . 235
Table 1106.11.11.2 Level 1 Ventilation Rate for
Class 2L Refrigerants . . . . . . . . . . . 236
1107.0 Machinery Room, Special Requirements . . . . . . . . . . . . . . . . 236
1107.1 General. . . . . . . . . . . . . . . . . . . . . 236
1108.0 Refrigeration Machinery Room Equipment and Controls . . . . . . . . 237
1108.1 General. . . . . . . . . . . . . . . . . . . . . 237
CMC § 1105.3 High relevance — show source text
(1) The addition of a second refrigerant is allowed by the equipment manufacturer and is in accordance with the manufacturer’s instructions.
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230 2025 CALIFORNIA MECHANICAL CODE
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
REFRIGERATION
A compressor or portion of a condensing unit supported from the ground shall rest on a concrete or other approved base extending not less than 3 inches (76 mm) above the adjoining ground level.
1105.3 Access. An unobstructed readily accessible opening and passageway not less than 36 inches (914 mm) in width and 80 inches (2032 mm) in height shall be provided and maintained to the compressor, valves required by this chapter, or other portions of the system requiring routine maintenance.
Exceptions:
(1) Refrigerant evaporators, suspended overhead, shall be permitted to use portable means of access.
(2) Air filters, brine control or stop valves, fan motors or drives, and remotely de-energized electrical connections shall be permitted to be provided access to an unobstructed space not less than 30 inches (762 mm) in depth, width, and height. Where an access opening is immediately adjacent to these items and the equipment is capable of being serviced, repaired, and replaced from this opening, the dimensions shall be permitted to be reduced to 22 inches (559 mm) by 30 inches (762 mm) provided the largest piece of equipment is removed through the opening.
(3) Cooling equipment, using Group A1 refrigerants or brine, located in an attic or furred space shall be permitted to be provided access by a minimum opening and passageway thereto of not less than 22 inches (559 mm) by 30 inches (762 mm).
(4) Cooling or refrigeration equipment, using Group A1 or B1 refrigerants or brine, located on a roof or on an exterior wall of a building, shall be permitted to be provided access as for furnaces in Section 304.3.
1105.4 Illumination and Service Receptacles. In addition to the requirements of Section 301.4, permanent luminaires shall be installed for equipment required by this code to be accessible or readily accessible. Such luminaires shall provide illumination to perform the required tasks for which access is provided. Control of the illumination source shall be provided at the access entrance.
Exceptions:
(1) Luminaires shall be permitted to be omitted where the fixed lighting of the building will provide the required illumination.
(2) Equipment located on the roof or on the exterior walls of a building.
1105.5 Ventilation of Rooms Containing Condensing Units. Where not in a refrigerant machinery room, rooms or spaces in which a refrigerant-containing portion of a condensing unit is installed shall be provided with ventilation in accordance with Section 1105.5.1 or Section 1105.5.2. Ventilation for machinery rooms shall comply with Section 1106.0.
1105.5.1 Permanent Gravity Ventilation Open- ings. Permanent gravity ventilation openings of not less
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(2) The resulting mixture does not change the refrigerant safety group. [ASHRAE 15:7.5.1.7]
CMC § 1103.2 High relevance — show source text
1103.2 Classification of Refrigeration Systems . . . . . . . . . . . . . . . . . . . . 227
1103.3 Higher Flammability Refrigerants . . . . . . . . . . . . . . . . . 227
1104.0 Requirements for Refrigerant and Refrigeration System Use . . . 227
1104.1 System Selection . . . . . . . . . . . . . 227
1104.2 Refrigerant Concentration Limit (RCL) . . . . . . . . . . . . . . . . . . 227
Table 1104.1 Permissible Refrigeration Systems . . . . . . . . . . . . . . . . . . . . 228
1104.3 Institutional Occupancies . . . . . . . 229
1104.4 Industrial Occupancies and Refrigerated Rooms . . . . . . . . . . . 229
1104.5 Flammable Refrigerants . . . . . . . . 229
2025 CALIFORNIA MECHANICAL CODE
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
TABLE OF CONTENTS
1104.6 Group A2L Refrigerants for Human Comfort . . . . . . . . . . . . . . 229
110.4.7 Applications for Human Comfort and for Nonindustrial
Occupancies. . . . . . . . . . . . . . . . . 230
1104.8 Refrigerant Type and Purity . . . . . 230
1104.9 Changing Refrigerants . . . . . . . . . 231
1105.0 General Requirements . . . . . . . . . 231
1105.1 Human Comfort . . . . . . . . . . . . . . 231
1105.2 Supports and Anchorage . . . . . . . 231
1105.3 Access . . . . . . . . . . . . . . . . . . . . . 231
1105.4 Illumination and Service
Receptacles . . . . . . . . . . . . . . . . . 231
1105.5 Ventilation of Rooms
Containing Condensing Units . . . . 231
1105.6 Prohibited Locations . . . . . . . . . . . 232
1105.7 Condensate . . . . . . . . . . . . . . . . . 232
1105.8 Defrost . . . . . . . . . . . . . . . . . . . . . 232
1105.9 Overflows . . . . . . . . . . . . . . . . . . . 232
1105.10 Condensate, Defrost, and Overflow Disposal. . . . . . . . . . . . . 232
1105.11 Refrigerant Port Protection . . . . . . 232
1105.12 Storage . . . . . . . . . . . . . . . . . . . . . 232
1106.0 Refrigeration Machinery Rooms . . 232
1106.1 Where Required . . . . . . . . . . . . . . 232
1106.2 Refrigeration Machinery Room, General Requirements . . . . . . . . . 232
CMC § 304.3. High relevance — show source text
(3) Cooling equipment, using Group A1 refrigerants or brine, located in an attic or furred space shall be permitted to be provided access by a minimum opening and passageway thereto of not less than 22 inches (559 mm) by 30 inches (762 mm).
(4) Cooling or refrigeration equipment, using Group A1 or B1 refrigerants or brine, located on a roof or on an exterior wall of a building, shall be permitted to be provided access as for furnaces in Section 304.3.
1105.4 Illumination and Service Receptacles. In addition to the requirements of Section 301.4, permanent luminaires shall be installed for equipment required by this code to be accessible or readily accessible. Such luminaires shall provide illumination to perform the required tasks for which access is provided. Control of the illumination source shall be provided at the access entrance.
Exceptions:
(1) Luminaires shall be permitted to be omitted where the fixed lighting of the building will provide the required illumination.
(2) Equipment located on the roof or on the exterior walls of a building.
1105.5 Ventilation of Rooms Containing Condensing Units. Where not in a refrigerant machinery room, rooms or spaces in which a refrigerant-containing portion of a condensing unit is installed shall be provided with ventilation in accordance with Section 1105.5.1 or Section 1105.5.2. Ventilation for machinery rooms shall comply with Section 1106.0.
1105.5.1 Permanent Gravity Ventilation Open- ings. Permanent gravity ventilation openings of not less
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(2) The resulting mixture does not change the refrigerant safety group. [ASHRAE 15:7.5.1.7]
1104.9 Changing Refrigerants. Changes of refrigerant in an existing system to a refrigerant with a different refrigerant designation shall only be allowed where in accordance with Section 1104.9.1 through Section 1104.9.4. [ASHRAE 15:5.3]
1104.9.1 Approval. The change of refrigerant shall be approved by the owner. [ASHRAE 15:5.3.1] 1104.9.2 Procedures. The change of refrigerant shall be in accordance with one of the following:
(1) Written instructions of the original equipment manufacturer.
(2) An evaluation of the system by a registered design professional or by an approved nationally recognized testing laboratory that validates safety and suitability of the replacement refrigerant.
(3) Approval of the Authority Having Jurisdiction.
[ASHRAE 15:5.3.2]
1104.9.3 Replacement Refrigerant of Same Clas- sification. Where the replacement refrigerant is classified into the same safety group, requirements that were applicable to the existing system shall continue to apply.
[ASHRAE 15:5.3.3]
1104.9.4 Replacement Refrigerant of Different Classification. Where the replacement refrigerant is classified into a different safety group, the system shall comply with the requirements of this chapter for a new installation, and the change of refrigerant shall require Authority Having Jurisdiction approval. [ASHRAE 15:5.3.4]
1105.0 General Requirements.
CMC § 220.0 High relevance — show source text
Recycled . . . . . . . . . . . . . . . . . . . . . . . . 220.0, 1104.8.2 Refrigerant designation, definition . . . . . . . . . . . . 220.0 Requirements for . . . . . . . . . . . . . . . . . . . . . . . . . 1104.0 Safety classification, definition . . . . . . . . . . . . . . . 220.0
Storage of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1105.12
Types used . . . . . . . . . . . . 1102.3, 1104.8, Table 1102.3
Zeotropic, definition. . . . . . . . . . . . . . . . . . . . . . . . 228.0
REFRIGERATION EQUIPMENT
Access. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1105.3
Coils . . . . . . . . . . . . . . . . . 310.6, 903.2.6, 904.8, 905.7
Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1108.0
Identification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1115.0
Illumination and
service receptacles . . . . . . . . . . . . . . . . . . . . . 1105.4
Location of . . . . . . . . . . . . . . . . . . . . . . . 1104.2, 1105.0
Refrigeration recovery . . . . . . . . . . . . . . . . . . . . . 1101.2 Supports and anchorage. . . . . . . . . . . . . . . . . . . 1105.2
Testing of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1116.0 Valves. . . . . . . . . (see Valves, for refrigeration systems)
REFRIGERATION
MACHINERY ROOMS
A2L. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1106.11
B2L. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1106.11
Definition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220.0
General . . . . . . . . . . . . . . . . . . . . . . . . . . 1106.0, 1106.2
REFRIGERATION SPACES
CMC § 1105.4 High relevance — show source text
Illumination and
service receptacles . . . . . . . . . . . . . . . . . . . . . 1105.4
Location of . . . . . . . . . . . . . . . . . . . . . . . 1104.2, 1105.0
Refrigeration recovery . . . . . . . . . . . . . . . . . . . . . 1101.2 Supports and anchorage. . . . . . . . . . . . . . . . . . . 1105.2
Testing of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1116.0 Valves. . . . . . . . . (see Valves, for refrigeration systems)
REFRIGERATION
MACHINERY ROOMS
A2L. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1106.11
B2L. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1106.11
Definition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220.0
General . . . . . . . . . . . . . . . . . . . . . . . . . . 1106.0, 1106.2
REFRIGERATION SPACES
Concentration limit. . . . . . . 1102.3, 1104.2, Table 1102.3
Industrial occupancies. . . . . . . . . . . . . . . . . . . . . 1104.4
Institutional occupancies . . . . . . . . . . . . . . . . . . . 1104.3
Nonconnecting spaces . . . . . . . . . . . . . . . . . . . 1104.2.2
Refrigerated spaces . . . . . . . . . . . . . . . . . . . . . . 1104.4
Ventilated spaces . . . . . . . . . . . . . . . . . . . . . . . 1104.2.3
Volume calculation . . . . . . . . . . . . . . . . . . . . . . 1104.2.1
REFRIGERATION SYSTEM CLASSIFICATION
Definition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220.0
High-probability systems. . . . . . . . . . . . . . . . . . 1103.2.1
Higher flammability refrigerants. . . . . . . . . . . . . . 1103.3
Low-probability . . . . . . . . . . . . . . . . . . . . . . . . . 1103.2.2
REFRIGERATION SYSTEMS
Absorption . . . . . . . . . . . . . . . . . . . . . . . . . 220.0, 307.4
CMC § 1104.8 Medium relevance — show source text
1104.8 Refrigerant Type and Purity. Refrigerants shall be of a type specified by the equipment manufacturer. Unless otherwise specified by the equipment manufacturer, refrigerants used in new equipment shall be of purity in accordance with AHRI 700.
1104.8.1 Recovered Refrigerants. Recovered refrigerants shall not be reused except in the system from which they were removed, or as provided in Section 1104.8.2 or Section 1104.8.3. When contamination is evident by discoloration, odor, acid test results, or system history, recovered refrigerants shall be reclaimed in accordance with Section 1104.8.3 before reuse. [ASHRAE 15:7.5.1.4]
1104.8.2 Recycled Refrigerants. Recycled refrigerants shall not be reused except in systems using the same refrigerant and lubricant designation and belonging to the same owner as the systems from which they were removed. Where contamination is evident by discoloration, odor, acid test results, or system history, recycled refrigerants shall be reclaimed in accordance with Section 1104.8.3.
Exception: Drying shall not be required in order to use recycled refrigerants where water is the refrigerant, is used as an absorbent or is a deliberate additive.
[ASHRAE 15:7.5.1.5]
1104.8.3 Reclaimed Refrigerants. Used refrigerants shall not be reused in a different owner’s equipment unless tested and found to be in accordance with the
requirements of AHRI 700. Contaminated refrigerants shall not be used unless reclaimed and is in accordance
with AHRI 700. [ASHRAE 15:7.5.1.6]
1104.8.4 Mixing. Refrigerants with different refrigerant designations shall only be mixed in a system in accordance with the following:
(1) The addition of a second refrigerant is allowed by the equipment manufacturer and is in accordance with the manufacturer’s instructions.
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230 2025 CALIFORNIA MECHANICAL CODE
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
REFRIGERATION
A compressor or portion of a condensing unit supported from the ground shall rest on a concrete or other approved base extending not less than 3 inches (76 mm) above the adjoining ground level.
1105.3 Access. An unobstructed readily accessible opening and passageway not less than 36 inches (914 mm) in width and 80 inches (2032 mm) in height shall be provided and maintained to the compressor, valves required by this chapter, or other portions of the system requiring routine maintenance.
Exceptions:
(1) Refrigerant evaporators, suspended overhead, shall be permitted to use portable means of access.
(2) Air filters, brine control or stop valves, fan motors or drives, and remotely de-energized electrical connections shall be permitted to be provided access to an unobstructed space not less than 30 inches (762 mm) in depth, width, and height. Where an access opening is immediately adjacent to these items and the equipment is capable of being serviced, repaired, and replaced from this opening, the dimensions shall be permitted to be reduced to 22 inches (559 mm) by 30 inches (762 mm) provided the largest piece of equipment is removed through the opening.
CMC § 1106.2.6. Medium relevance — show source text
(1) The space(s) containing the machinery is (are) separated from other occupancies by tight construction with tightfitting doors.
(2) Access is restricted to authorized personnel.
(3) Refrigerant detectors are installed with the sensing location and alarm level as required in refrigeration machinery rooms in accordance with Section 1106.2.6.
(4) Open flames and surfaces exceeding 800°F (427°C) shall not be permitted where a Group A2, B2, A3, or B3 refrigerant, is used.
(5) Electrical equipment that is in accordance with Class 1, Division 2, of NFPA 70 where the quantity of a Group A2, B2, A3, or B3 refrigerant in an independent circuit is capable of exceeding 25 percent of the lower flammability limit (LFL) upon release to the space based on the volume determined in accordance with Section 1104.2.1 through Section 1104.2.3.
(6) Refrigerant containing parts in systems exceeding 100 horsepower (74.6 kW) compressor drive power, except evaporators used for refrigeration or dehumidification, condensers used for heating, control and pressure-relief valves for either, low-probability pumps, and connecting piping, are located in a machinery room or outdoors.
[ASHRAE 15:7.2.2]
1104.5 Flammable Refrigerants. The total of Group A2, B2, A3, and B3 refrigerants, other than Group A2L and B2L refrigerants shall not exceed 1100 pounds (498.9 kg) without approval by the Authority Having Jurisdiction. Institutional Occupancies shall comply with Section 1104.3. Machinery rooms required in accordance with Section 1106.0 based on flammability shall be constructed and maintained in accordance with Section 1106.2.1 through Section 1106.2.6 and Section 1106.11 for Group A2L and B2L refrigerants. 1104.6 Group A2L Refrigerants for Human Comfort. High-probability systems using Group A2L refrigerants for human comfort applications shall comply with this section.
[ASHRAE 15:7.6]
1104.6.1 Refrigerant Concentration Limits. Occupied spaces shall comply with the releasable charge limitations of the equipment listing and ASHRAE 15. Unoccupied spaces with refrigerant containing equipment, not including continuous piping or tubing, shall comply with the releasable charge limitations of the equipment listing or Section 1104.6.4. {ASHRAE 15:7.6.1-7.6.1.2}
1104.6.2 Listing and Installation Requirements. Refrigeration systems shall be listed and shall be installed in accordance with listing, the manufacturer’s instructions, and any markings on the equipment restricting the installation. [ASHRAE 15:7.6.2]
1104.6.2.1 Nameplate. The nameplate required by Section 1115.5 shall include a symbol indicating that a flammable refrigerant is used, as specified by the product listing. [ASHRAE 15:7.6.2.1]
1104.6.2.2 Labeling. A label indicating a flammable refrigerant is used shall be placed adjacent to service ports and other locations where service involving components containing refrigerant is performed, as specified by the product listing.
CMC § 11-01 Medium relevance — show source text
The developer or his contractor shall provide all necessary trenching, secondary and service conduit (when required), and shall be responsible for the location and final grade of the utility islands
The required location for the meter equipment is at the front of the mobile home (see Figure 1 on Page 4). Alternate locations for the meter pedestal are indicated by the shaded areas in Figure 1 on Page 4.
PG&E shall install the secondary and service lateral cables in accordance with current engineering standards and construction methods.
Maintain a 36-inch (minimum) work space clearance from the meter face and from any access panel to PG&E facilities on the enclosure. Maintain a 36-inch (minimum) clearance from the meter equipment to other utility equipment such as gas, water or sewer. Refer to the National Electrical Code and the Authority Having Jurisdiction for the allowed working space requirements and if the 36-inch (minimum) clearance shown in Figure 3 and Figure 4 on Page 5 may be reduced to 12 inches for pedestal designs which have the meter and all access panels (both PG&E’s and customer’s) located on the same side of the pedestal.
Before PG&E has installed the cable, the developer or his contractor shall then:
A. Install the electric meter pedestal in place over the conduit. Position the pedestal so the meter socket faces toward the street as shown on Page 5 or away from mobile home. Maintain the work space and clearances as described in Note 4.
B. Install and connect a copper grounding conductor from the pedestal grounding lug to an N.E.C. approved ground electrode system. The grounding connection shall not be made to a gas piping system. The customer shall be responsible for bonding and grounding all exposed non-current-carrying metal parts in accordance with the applicable electric codes and local ordinances. PG&E prefers, but does not require, the grounding electrode conductor wire to be protected against physical damage by rigid steel conduit or armored cladding. Refer to the NEC for any required clearance distance of the ground rod away from the pedestal. The top of the ground rod may be exposed or buried as required to meet the applicable electric codes. Exposed ground rods should be placed so they are not a tripping hazard.
C. Bond the service neutral termination lug to the meter pedestal by means of a bonding screw, or by continuing the grounding conductor between the grounding lug and the neutral lug.
Rev. #06: 11-01-18 052521 Page 1 of 8
Greenbook EMWP Electrical Service Requirements for Mobile Home Developments
D. Backfill around the pedestal to provide good support, plumb and level the pedestal, and pour the concrete base support or island. The concrete surface should be no more than 1-inch above grade and 1-inch to 2-inch below the bottom of the utility section opening.
E. Backfill all trenches, and furnish any imported backfill material required.
PG&E shall connect the service lateral conductors to the termination lugs in the meter pedestal, install and seal the pull section panel, and blank off and seal the meter socket.
PG&E shall set the meter upon request for service, after required permits and inspections have been obtained from city or county inspection authorities.
See Figure 1 on Page 4 for a typical electric distribution system layout for a mobile home development.
PG&E shall design its facilities so that the short-circuit duty at the electric service entrance will not exceed 10,000 amps.
CMC § 301.1 Medium relevance — show source text
301.1 Applicability. This chapter covers general requirements for heating, ventilating, air-conditioning, refrigeration, miscellaneous heat-producing, and energy-utilizing equipment or appliances. Such equipment or appliances shall comply with the requirements of this code.
301.2 Approval. Equipment or appliance shall be approved by the Authority Having Jurisdiction for safe use or comply with applicable nationally recognized standards as evidenced by the listing and label of an approved agency. A list of accepted standards is included in Chapter 18. Defective materials or parts shall be replaced in such a manner as not to invalidate an approval.
301.3 Design of Equipment. The installer or contractor shall furnish satisfactory evidence that the appliance is constructed in accordance with the requirements of this code. The permanently attached label of an approved agency shall be permitted to be accepted as such evidence. 301.4 Electrical Connections. For equipment regulated by this code:
(1) Equipment requiring electrical connections of more than 50 volts shall have a positive means of disconnect adjacent to and in sight from the equipment served.
Exception: Other power disconnect means shall be acceptable where in accordance with the California Elec- trical Code .
(2) A 120 volt receptacle shall be located within 25 feet (7620 mm) of the equipment for service and maintenance purposes. The receptacle outlet shall be on the supply side of the disconnect switch. The receptacle need not be located on the same level as the equipment.
(3) Electrical wiring, controls, and connections to equipment and appliances regulated by this code shall be in accordance with the California Electrical Code . 301.5 Oil-Burning Appliances. The tank, piping, and valves for appliances burning oil shall be installed in accordance with the requirements of NFPA 31.
301.6 Personnel Protection. A metal guard shall be provided around exposed flywheels, fans, pulleys, belts, and moving machinery that are portions of a heating, ventilating, or refrigerating system. 301.7 OSHPD 1R. [OSHPD 1R] For OSHPD 1R, refer to Section 309 of California Existing Building Code for general requirements.
302.0 Materials – Standards and Alternates.
302.1 Minimum Standards. Listed pipe, pipe fittings, appliances, appurtenances, equipment, materials, and devices used in a mechanical system shall be listed (third-party certified) by a listing agency (accredited conformity assessment
body) as complying with the approved applicable recognized standards referenced in this code, and shall be free from defects. Unless otherwise provided for in this code, materials, appurtenances, or devices used or entering into the construction of mechanical systems, or parts thereof, shall be submitted to the Authority Having Jurisdiction for approval prior to being installed.
302.1.1 Marking. Each length of pipe and each pipe fitting, material, and device used in a mechanical system shall have cast, stamped, or indelibly marked on it any markings required by the applicable referenced standards and listing agency, and the manufacturer’s mark or name, which shall readily identify the manufacturer to the end user of the product. Where required by the approved standard that applies, the product shall be marked with the weight and the quality of the product. Materials and devices used or entering into the construction of mechanical systems, or parts thereof, shall be marked and identified in a manner satisfactory to the Authority Having Jurisdiction. Such marking shall be done by the manufacturer. Field markings shall not be acceptable.
CMC § 1.11.0. Medium relevance — show source text
5_||||||||||X|X|X||X|X|||||||||| |321.0||||||||||X||X|X|X|X|||||||||| |322.0
||||||||||X||X|X|X|X|||||||||| |323.0
||||||||||X|X|X||X|X|||||||||| |324.0||||||||||X|X|X|X|X|X|||||||||| |325.0||||||||||||X|||||||||||||This state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.0.
2025 CALIFORNIA MECHANICAL CODE 49
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50 2025 CALIFORNIA MECHANICAL CODE
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CHAPTER 3
GENERAL REGULATIONS
301.0 General.
301.1 Applicability. This chapter covers general requirements for heating, ventilating, air-conditioning, refrigeration, miscellaneous heat-producing, and energy-utilizing equipment or appliances. Such equipment or appliances shall comply with the requirements of this code.
301.2 Approval. Equipment or appliance shall be approved by the Authority Having Jurisdiction for safe use or comply with applicable nationally recognized standards as evidenced by the listing and label of an approved agency. A list of accepted standards is included in Chapter 18. Defective materials or parts shall be replaced in such a manner as not to invalidate an approval.
301.3 Design of Equipment. The installer or contractor shall furnish satisfactory evidence that the appliance is constructed in accordance with the requirements of this code. The permanently attached label of an approved agency shall be permitted to be accepted as such evidence. 301.4 Electrical Connections. For equipment regulated by this code:
(1) Equipment requiring electrical connections of more than 50 volts shall have a positive means of disconnect adjacent to and in sight from the equipment served.
Exception: Other power disconnect means shall be acceptable where in accordance with the California Elec- trical Code .
(2) A 120 volt receptacle shall be located within 25 feet (7620 mm) of the equipment for service and maintenance purposes. The receptacle outlet shall be on the supply side of the disconnect switch. The receptacle need not be located on the same level as the equipment.
(3) Electrical wiring, controls, and connections to equipment and appliances regulated by this code shall be in accordance with the California Electrical Code . 301.5 Oil-Burning Appliances. The tank, piping, and valves for appliances burning oil shall be installed in accordance with the requirements of NFPA 31.
CMC § 304.4.3 Medium relevance — show source text
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GENERAL REGULATIONS
304.4.3 Work Platform. A level working platform not less than 30 inches by 30 inches (762 mm by 762 mm) shall be provided in front of the service side of the appliance. [NFPA 54:9.5.2]
Exception: A working platform need not be provided where the furnace is capable of being serviced from the required access opening. The furnace service side shall not exceed 12 inches (305 mm) from the access opening. 304.4.4 Lighting and Convenience Outlet. A permanent 120 V receptacle outlet and a luminaire shall be installed near the appliance. The switch controlling the luminaire shall be located at the entrance to the passageway. [NFPA 54:9.5.3]
305.0 Location.
305.1 Installation in Residential Garages. Appliances in residential garages and in adjacent spaces that open to the garage and are not part of the living space of a dwelling unit shall be installed so that all heating elements, switches, burners, and burner-ignition devices are located not less than 18 inches (457 mm) above the floor. Exception: Listed flammable vapor ignition resistant (FVIR) appliances. {NFPA 54:9.1.10.1} 305.1.1 Physical Damage. Appliances installed in garages, warehouses, or other areas subject to mechanical damage shall be guarded against such damage by being installed behind protective barriers or by being elevated or located out of the normal path of vehicles. 305.1.2 Access from the Outside. Where appliances are installed in a separate, enclosed space having access only from outside of the garage, such appliances shall be permitted to be installed at floor level, providing the required combustion air is taken from the exterior of the garage. [NFPA 54:9.1.10.3] 305.1.3 Cellulose Nitrate Plastic Storage. Heating equipment located in rooms where cellulose nitrate plastic is stored or processed shall be in accordance with the fire code.
305.2 Pit Location. Where excavation is necessary to install an appliance, the depth shall extend not less than 6 inches (152 mm) below and 12 inches (305 mm) on all sides of the appliance, except on the service side, which shall have 30 inches (762 mm). Where the depth of the excavation for either the appliance or passageway exceeds 12 inches (305 mm), walls shall be lined with concrete or masonry 4 inches (102 mm) above the adjoining ground level. Exception: [HCD 1 & HCD 2] Liquefied petroleum gas (LP-Gas) appliances as described in Section 303.7.1. 305.3 Flood Hazard Areas. For buildings located in flood hazard areas, heating, ventilating, air-conditioning, refrigeration, miscellaneous heat-producing, and energy-utilizing equipment and appliances shall be elevated at or above the elevation in accordance with the building code for utilities and attendant equipment or the elevation of the lowest floor, whichever is higher. Exception: Equipment and appliances shall be permitted to be located below the elevation in accordance with the build
Frequently asked questions
Must the luminaire switch always be at the entrance to the access opening?
Yes. § 1105.4 requires control of the illumination source to be provided at the access entrance unless the fixed building lighting already provides the required illumination.
Can I use a portable lamp instead of a permanent luminaire?
Not for spaces where the code requires permanent luminaires; § 1105.4 calls for permanent luminaires unless the building’s fixed lighting is adequate or the equipment is on a roof/exterior wall (exception).
How close must the 120 V receptacle be to the equipment?
A 120 V receptacle must be located within 25 feet (7620 mm) of the equipment for service and maintenance per § 301.4 (referenced by § 1105.4).
Is it acceptable to put a compressor directly on grade if it’s small?
No. A ground-supported compressor must rest on a concrete or approved base extending not less than 3 in (76 mm) above the adjoining ground per § 1105.2.
Can access openings be smaller than 36" × 80"?
Yes — § 1105.3 contains exceptions for specific components and locations allowing smaller openings (for example 30" clearances or 22" × 30" openings when conditions in the exceptions are met). Verify the exact exception language before applying.
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