300.25 Exit Enclosures (Stair Towers).

Where an exit enclosure is required to be separated from the building, only electrical wiring methods serving equipment permitted by the authority having jurisdiction in the exit enclosure shall be installed within the exit enclosure.
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Where an exit enclosure is required to be separated from the building, only electrical wiring methods serving equipment permitted by the authority having jurisdiction in the exit enclosure shall be installed within the exit enclosure.

Code Change Summary: New code section on wiring in exit enclosures.

Section 7.1.3.2.1(10)(b) of the 2018 NFPA 101 Life Safety Code, prohibits installing conduits in a separated exit enclosure  or stair tower unless the conduits are associated with the exit enclosure. Something this important should also be in the NEC® and not hidden away in NFPA 101, where electrical designers, inspectors, and installers may not be made aware of it.

There are many codes and standards to be aware of for those in the construction trade. Electricians truly appreciate when most of the rules they must adhere to are in the same code book. It can be costly to correct an overzealous conduit installation in a stairwell and a bit frustrating when the NEC® makes no mention of such a major violation.

The code language in NFPA 101 Section 7.1.3.2.1(10)(b) prohibits “conduit” but the additional explanation in Annex A7.1.3.2.1(10)(b) allows penetrations for electrical wiring where the wiring supplies equipment permitted by the authority having jurisdiction to be located within the exit enclosure. This can include security systems, public address systems, and fire department emergency communications devices.

The new 2020 code language in 300.25 expands the requirement to “wiring methods” which is much broader than just “conduits”.

Below is a preview of the NEC®. See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2020 NEC® edition of NFPA 70.

2017 Code Language:

This code section did not exist.

2020 Code Language:

N 300.25 Exit Enclosures (Stair Towers). Where an exit enclosure is required to be separated from the building, only electrical wiring methods serving equipment permitted by the authority having jurisdiction in the exit enclosure shall be installed within the exit enclosure.

Informational Note: For more information, refer to NFPA 101-2018, Life Safety Code, 7.1.3.2.1(10)(b).

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300.25 Exit Enclosures (Stair Towers).

Below is a Real Question from our Electrical Continuing Education Courses for Electrical License Renewal:

Based on the 2020 NEC, which of the following is true?

A: The requirements in 300.25 apply to all exit enclosures.
B: The requirements in 300.25 only apply to exit enclosures that are required to be separated from the building.
C: Section 300.25 only applies to exterior exit enclosures.
D: Section 300.25 only applies to interior exit enclosures.
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