Code of Massachusetts Regulations
527 CMR - BOARD OF FIRE PREVENTION REGULATIONS
Title 527 CMR 12.00 - Massachusetts Electrical Code

Rule 1. All installations, repairs, maintenance, and removal of electrical wiring and electrical fixtures used for light, heat, power, signaling and communications purposes in buildings and structures subject to the provisions of M.G.L. c. 143 shall be reasonably safe to persons and property.

Rule 2. Conformity of installations, repairs, maintenance, and removal of electrical wiring and electrical fixtures used for light, heat, power, signaling and communications with applicable regulations set forth in the Code, which is hereby filed with the Secretary of the Commonwealth shall be considered as complying with these requirements.

Rule 3. Additions or modifications to an existing installation shall be made in accordance with this Code without bringing the remaining part of the installation into compliance with the requirements of this Code. The installation shall not create a violation of this Code, nor shall it increase the magnitude of an existing violation.

Rule 4. Where an actual hazard exists, the owner of the property shall be notified in writing by the authority enforcing this Code. The notification shall contain specifications of the actual hazard that exists, together with a reference to the rule of this Code that is now in violation. (See M.G.L. c. 166, §§ 32 and 33, for enforcement authority.)

Rule 5. References are made in this code to other standards. Those standards, where duly adopted by law or regulation, may be enforced by the appropriate official. They are not considered part of this Code and they are not enforceable under M.G.L. c. 143, § 3L. For Massachusetts Building Code references, see Appendix A.

Rule 6. The approving authority may be guided in his approval of specific items of equipment and materials contemplated by the Code, by proof that such equipment and materials have been tested and conform to suitable recognized industry standards.

Rule 7.527 CMR 12.00 shall be effective on all installations for which a permit has been granted subsequent to February 28, 2023.

Rule 8. In accordance with the provisions of M.G.L. c. 143 § 3L, the permit application form to provide written notice of installation of wiring shall be uniform throughout the Commonwealth, and applications shall be filed on the prescribed form. Electronic transmittals of this form shall be permitted when done in accordance with the Uniform Electronic Transactions Act (M.G.L. c. 110G). After a permit application has been accepted by an Inspector of Wires appointed pursuant to M.G.L c. 166, § 32, an electrical permit shall be issued to the person, firm or corporation stated on the permit application. Such entity shall be responsible for the notification of completion of the work as required in M.G.L. c. 143, § 3L.

Permits shall be limited as to the time of ongoing construction activity, and may be deemed by the Inspector of Wires abandoned and invalid if he or she has determined that the authorized work has not commenced or has not progressed during the preceding 12-month period. Upon written application, an extension of time for completion of work shall be permitted for reasonable cause. A permit shall be terminated upon the written request of either the owner or the installing entity stated on the permit application.

Rule 9. Installations, repairs, maintenance, or removals covered by 527 CMR 12.00 shall also comply with M.G.L. c. 141.

Rule 10. Electrical installations, repairs, maintenance, or removals shall not be concealed or covered from view until inspected by the inspector of wires within and not more than 24 hours for exterior or interior excavations nor more than 72 hours for exterior or interior installations after proper notice to the inspector, Saturdays, Sundays, and holidays excluded.

Rule 11. Electrical installations that appear incompatible with GFCI protection as covered in 210.8 Exception of this Code, regardless of the code requirements in effect at the time when the permit as described in Rule 8 was issued, or when the installation was completed, shall be inspected by a qualified person. The inspection shall review all field elements of the branch-circuit equipment grounding return path, and the quality of any field-accessible cord connections if applicable. The inspection shall be documented, subject to audit by the Inspector of Wires, and inspected by him or her as deemed necessary. Installations of listed equipment that, under normal operating conditions, are found to be incompatible with GFCI protective devices as made available by the manufacturer of the circuit protection currently installed shall be excused from providing GFCI protection. If not connected to an individual branch circuit, incompatible equipment shall be directly wired or connected to a single receptacle, and the circuit shall be arranged so required GFCI protection is retained for the remaining outlets. The inspection documentation required by this rule shall constitute the notice required in Rule 8 and no additional notice shall be required for corrections applied accordingly. The location and the date of this determination shall be forwarded to the Department of Fire Services for inclusion in a central registry of such allowances. The report shall also include the appliance manufacturer and model, together with the identity of the GFCI protective device. This rule shall expire on January 1, 2026.

90.2(D)(5). Delete (d) and revise (c) to read as follows:

90.4. Revise 90.4 by replacing 90.4(A) and 90.4(B) as follows; Sections 90.4(C) and 90.4(D) remain unchanged from the NEC:

90.6. Revise to read as follows:

90.10. Add new section numbered 90.10 to read:

110.14(A). Delete the last sentence of the first paragraph and insert the following two sentences in its place:

Connection by means of wire binding screws or studs and nuts having upturned lugs or equivalent shall be permitted for 10 AWG or smaller solid conductors, or conductors with Class B stranding. Where Class C stranded conductors are terminated on and not looped through such terminals, the uninsulated strands shall be completely enclosed within the termination, or the strands at the terminals shall be made solid.

110.24. Insert an additional informational note as follows:

Informational Note No. 3. The marking required in this section is useful in determining compliance with 110.9, but must be understood as transitory and requiring reconfirmation prior to the performance of additional electrical work. This and numerous other locations in the NEC require field markings of the available fault current. A major component of this current is usually that contributed by the utility through the service. The utility contribution is inherently dynamic in value, particularly on the medium voltage portions of their distributions. Without notice, automatic line sectionalizing can transfer a service from the tail end of one circuit to the head end of an adjacent circuit, with a significant increase in available fault current. In addition, there are numerous sources of on-site contributions to available fault current.

110.26(A)(1). Add a fourth paragraph (d) as follows:

210.8. Insert the following exception after the first paragraph:

Exception: Permanently connected equipment and cord-and-plug connected stationary equipment that is listed, but incompatible with GFCI protective devices as made available by the manufacturer of the circuit protection currently installed, shall be permitted to omit such protection provided it is installed and inspected in accordance with the provisions of Rule11 of this Code. This exception shall expire on January 1, 2026.

Revise the second paragraph to read as follows:

For the purposes of this section, when determining distance from receptacles the distance shall be measured as the shortest path the supply cord of equipment connected to the receptacle would follow without piercing a floor, wall, ceiling, fixed barrier, or without passing through a cabinet door opening, doorway, or window.

210.8(A)(7) Revise to read as follows:

210.8(A)(8). Revise to read as follows:

210.8(B)(7) Revise to read as follows:

210.8(F). Delete this requirement.

210.12(B). Replace the parent text and list items with the following:

All 120-volt, single-phase, 15- and 20-ampere branch circuits supplying outlets or devices installed in dwelling units shall be protected by any of the means described in 210.12(A)(1) through (A)(6).

210.21(B) Insert a new fifth paragraph as follows:

210.25(B) Add an exception as follows:

Exception: Branch circuits supplying lighting outlets in common areas on the same floor as a dwelling unit in a new or existing two-family or an existing three-family building shall be permitted to be supplied from equipment that supplies one or more of those dwelling units.

210.52(A)(2)(1) Revise to read as follows:

Any space 600 mm (2 ft) or more in width (including space measured around corners) and unbroken along the floor line by doorways, fireplaces, stationary appliances, and similar openings.

210.52(A)(4) Delete 210.52(A)(4) in its entirety.

210.52(C) Make the following three revisions:

215.15 Barriers. Revise to read as follows:

"Barriers shall be placed in panelboards, switchboards, switchgear, and motor control centers such that no energized, uninsulated, ungrounded supply terminal is exposed to inadvertent contact by persons or maintenance equipment while servicing load terminations. This requirement shall be applied to the supply terminals of equipment supplied by feeder taps as covered in 240.21(B) or by transformer secondary conductors as covered in 240.21(C), in all instances where the equipment disconnecting means is located within the same enclosure, or is located remotely and also controls other loads."

220.40 Insert the following informational Note:

Informational Note No. 3: Beginning on January 1, 2024, cities and towns that have adopted the Specialized Stretch Energy Code will require new one- and two-family homes built with fossil fuel equipment to be pre-wired for future electrification conversion. For heating equipment, this will apply to heat pumps or to resistance heat or to both as applicable. The requirements will also extend to fossil-fueled major appliances. This will effectively require the service, and intermediate feeders if present, to be wired based on the future requirements as if it were an all-electric home at the time the home is built. In addition, where this Energy Code is in effect, the advance installation of branch-circuit wiring for all future electrical equipment that would be required to accomplish the future conversion from fossil fuel applications must be in place, routed to locations that are appropriate to meet this intent.

225.30(F) Revise to read as follows:

225.31 Exception No. 1. Revise to read as follows:

Exception No. 1: For large capacity multibuilding industrial or institutional installations under single management where documented safe switching procedures are established and maintained for disconnection, and where the disconnection is monitored by qualified individuals, the disconnecting means shall be permitted to be located elsewhere on the premises.

230.85 Make the following changes in this Section:

250.130(C) Delete this subsection.

250.140(B) Revise the final clause to read: "and the grounded conductor complies with list item (4)." Delete list item (5).

300.4(D) Delete this subsection.

300.5(A) Add an informational note to this subsection as follows:

Informational Note: Cables suitable for direct burial are often sleeved in various raceways for design reasons. If such cable is installed with sufficient cover for direct burial, then the characteristics of that raceway need not be evaluated. Other rules of this Code that apply to raceways generally may apply. See 300.5(H).

300.11(B) Revise this subsection as follows:

300.17 Add a second paragraph as follows:

Where different raceway wiring methods are joined together without a pull point at the transition, there shall not be more than the equivalent of four quarter bends (360° total) between pull points, e.g., conduit bodies and boxes.

305.15(A) In Note 4 to Table 305.15(A), insert the words "or institutional" after the word "industrial".

310.12 Delete the second paragraph.

310.15(C)(1) Delete the fourth itemized adjustment provision (d) covering AC and MC cable.

310.15(C)(1) Revise Table 310.15(C)(1) to read as follows:

1Number of Conductors is the total number of conductors in the raceway or cable, including spare conductors. The count shall be adjusted in accordance with 310.15(E) and (F), and shall not include conductors that are connected to electrical components but that cannot be simultaneously energized.

Informational Note: Overheating may occur where continuous, fully loaded conductor diversity is less than 50% and the number of current-carrying conductors exceeds nine. See 310.15(C).

314.29(A) Revise to read as follows:

320.80(A). Delete the last sentence of the first paragraph, which reads: "The 90°C (194°F) rating shall be permitted to be used for ampacity adjustment and correction calculations; however, the ampacity shall not exceed that for a 60 °C (140 °F) rated conductor."

334.10. Insert an exception to follow (3) to read as follows:

Exception to (2) and (3): For buildings or structures required to be of Type I or Type II construction, Type NM, or Type NMC cables shall be permitted to be used, provided that where so applied in buildings or structures exceeding three stories above grade, circuits run in Type NM or NMC cable shall not leave the floor or dwelling unit from which the circuits originate. Cables shall be installed within walls, floors, or ceilings that provide a thermal barrier of material that has at least a 15-minute finish rating as identified in listings of fire-rated assemblies.

334.12(A)(2). Revise to read as follows:

334.17. Revise to read as follows:

334.30. Revise 334.30 as follows [(A), (B), and (C) unchanged from the NEC]:

334.80. Delete the second paragraph and revise the first paragraph to read as follows:

338.10(B)(4). Insert an informational note as follows:

Informational Note: This section includes service entrance cables with a round configuration commonly known as SER cable. The interior installation of this cable is governed by the same rules as apply to nonmetallic sheathed cable.

338.10(B)(4)(a)(3). Revise to read as follows:

Where installed in thermal insulation, the ampacity shall be in accordance with the 60°C (140°F) conductor temperature rating. The maximum conductor temperature rating shall be permitted to be used for ampacity adjustment and correction purposes, if the final derated ampacity does not exceed that for a 60°C (140°F) rated conductor.

344.6. Add an exception as follows:

Exception: Rigid metal conduit made from nonferrous metals other than aluminum shall be permitted to be approved.

352.12. Add a new (F) to read as follows:

368.8. Insert a new Section 368.8 in Part I of Article 368 as follows:

368.14. Insert a new Section 368.14 in Part II of Article 368 as follows:

368.56(B). Revise the rule in list item (2) and the exception to (B)(2) to read as follows:

372.23. Revise this section to read as follows:

374.23. Revise this section to read as follows:

390.23. Revise this section to read as follows:

400.5. Revise Table 400.5(A)(3) to read as follows:

Informational Note: Overheating may occur where continuous, fully loaded conductor diversity is less than 50% and the number of current-carrying conductors exceeds nine. See 310.14(A)(3).

400.12(4). Revise the existing exception as follows:

Exception to (4): Flexible cord and cable shall be permitted to be installed in accordance with 368.56(B) and 590.4. For other applications, where the length of the cord from the supply termination to a suitable tension take-up device is limited to 2.5 m (8 ft), flexible cord shall be permitted to have one connection to the building surface.

400.17. Revise the second paragraph to read as follows:

Flexible cords and cables shall be permitted to be installed in raceways not longer than 15 m (50 ft) in length where required to protect the flexible cord or cable from physical damage. The ampacity of the conductors within a raceway shall be adjusted in accordance with Table 400.5(A)(3) based on the total number of current-carrying conductors within the raceway, and then further derated by a factor of 0.8, or the ampacity shall be calculated in accordance with 310.14(B). The raceway shall be exposed over its entire length.

406.4(D)(3). Delete the exception.

406.9(C). Replace the entire content with the following sentence: "Receptacles shall not be installed within

or directly over a bathtub or shower stall."

410.16(D). Revise items (1) through (4) to read as follows:

410.36(B). Add a second paragraph as follows:

In addition to, or lieu of, the mechanical fastening means, luminaires equaling or exceeding 1.8 kg (4 lb) shall be directly supported to the building structure or to approved intermediate supports rigidly secured to the building structure. The luminaire support shall be by wire, chain, or threaded rod of sufficient strength to carry the luminaire. Luminaires equal to or greater than 600 mm (2 ft), nominal, on a side shall be supported at each end of a diagonal axis regardless of weight.

440.14. Insert a second informational note as follows:

Informational Note No. 2: Article 440 generally only applies to equipment that incorporates hermetic refrigerant motor-compressors. See also 430.109(B) for specific provisions governing the disconnecting requirements for such equipment, wherever located, that uses a motor that is C hp or less.

517.13. Delete the Exception.

517.26. Delete (2), which would otherwise read: "Section 700.10(D) shall not apply."

680.4. Delete this requirement.

680.8. Insert an informational note ahead of 680.8(A) as follows:

Informational Note: Unlisted swimming pool pump motors have been observed in the field as having been supplied by their manufacturer with undersized cords, cords of excessive length, cord connectors on outdoor applications that are unsuitable for wet locations, and other violations of this Code. The fact that a manufacturer may supply them in this form does not excuse compliance with the rules of this Code.

Listed storable swimming pool pump motors with long factory-supplied cords are prominently marked as such and are not covered in Part II of Article 680. They are not manufactured for use with permanently installed pools and they need not be bonded where used as intended. See 680.31.

680.23(B)(2)(a) Amend this provision to read as follows:

680.23(F)(1) Wiring Methods. Revise the requirement to read as follows:

Branch circuit wiring on the supply side of enclosures and junction boxes connected to underwater luminaires and running in corrosive, wet, or below-grade locations shall comply with 680.14 or shall be liquidtight flexible nonmetallic conduit. Wiring methods in dry, noncorrosive locations within or on buildings shall be selected and run in accordance with the applicable requirements in Chapter 3. Wiring in all locations shall include an insulated or covered equipment grounding conductor of a wire type, sized in accordance with 250.122 but not smaller than 12 AWG.

(Exception unchanged from the NEC.)

680.26(B)(2)(b) Insert an additional paragraph to follow the five item list and reading as follows:

"This method shall only be permitted for above-ground pools."

680.74(A) Delete numbered paragraphs (3), (4), and (5). Delete Exception No. 1 and Exception No. 3, and designate Exception No. 2 as Exception.

690.31(D)(2) Revise the second sentence of the second paragraph to read as follows:

The labels shall be reflective, all letters shall be capitalized, and the letters shall have a minimum height of 9.5 mm (% in.) in white on a red background.

690.56 Insert the following Informational Note after the section title and before 690.56(A):

Informational Note: The Massachusetts Comprehensive Fire Code, 527 CMR 1.00, requires signage adjacent to the building or service disconnect that provides contact information and identifies the party responsible for the operation of the PV system.

Article 691. Delete this article.

700.10(D) Revise as follows:

700.12(H)(2)(2) In the third sentence, delete the word "also". Then delete the second sentence that reads:

Flexible cord- and plug-connection shall be permitted provided that the cord does not exceed 900 mm (3 ft) in length.