NEC 90.15: exceptions explained

What 90.15 Actually Says

NEC 90.15 covers demolition. The rule is simple on its face: electrical equipment and wiring that serves a structure or portion of a structure being demolished must be disconnected from all sources of supply before demolition begins. The code lives in Article 90 because it is a baseline expectation that runs across the whole book, not tied to one wiring method or occupancy.

The purpose is worker safety and property protection. A demolition crew cannot be assumed to know which conductors are live, which feeders loop through the space, or which service laterals still carry voltage. 90.15 pushes that verification back onto the qualified person doing the electrical work, consistent with 110.25 and the broader framework in NFPA 70E.

Read 90.15 alongside 90.2, which sets scope. If the installation falls under scope, the demolition requirement applies. The exceptions are where the field judgment happens.

How NEC Exceptions Work

Every exception in the NEC narrows a rule. It never expands one. If the main rule prohibits something, the exception lets you do it under stated conditions. If the main rule requires something, the exception lets you skip it under stated conditions. Nothing more.

Per 90.5(B), exceptions are enforceable code text. Informational notes are not. That distinction matters on inspection day. An inspector can write you up for missing an exception condition. An informational note is reference material only, useful for context but not a rule you can hang a variance on.

Field tip: when you cite an exception to an inspector, cite the parent rule first, then the exception number, then the specific condition you are meeting. "90.15, Exception No. 1, partial demolition with energized feeder serving occupied portion" lands better than "there's an exception."

Common Exception Patterns on 90.15

The typical exception allows portions of an electrical system to remain energized during partial demolition, provided the energized portion is isolated from the demolition zone and feeds a portion of the structure that remains in service. Think strip mall where one tenant space is being gutted while the neighbors stay open, or a hospital wing under renovation while adjacent wings run normally.

To use that exception in the field, you need to confirm three things:

• The energized conductors are not located within the demolition work area
• The feeder or branch circuit serves only the portion remaining in service
• The disconnection point for the demo area is identifiable, lockable, and documented

When any of those fail, you fall back to the main rule: disconnect everything feeding the demo zone before work starts. Do not try to stretch the exception by arguing intent. Inspectors and insurance adjusters read the literal text.

Coordinating With Other Articles

90.15 does not live alone. It pulls in requirements from 110.25 on the availability of disconnects, 230.85 for emergency disconnects on dwellings, and 225.41 for outdoor feeder disconnects. If you are demolishing a detached structure supplied by a feeder, 225.31 through 225.33 control where and how you open the feeder.

Service-entrance work is its own animal. Coordinate the utility shutdown before cutting or removing any service conductors. POCO rules often predate the demolition and are not waived by an NEC exception. 230.82 lists what is permitted on the line side of the service disconnect, which matters when you are staging a temporary service during a phased demo.

For equipment grounding and bonding during partial demo, 250.24 and 250.32 keep governing the portion that stays energized. Do not lift a grounding electrode conductor or main bonding jumper because "it's all coming out anyway." If any part remains in service overnight, the grounding system has to remain intact.

Field Checklist Before You Cut

Before you touch a conductor on a demo job, walk the site with the prints and a meter. Verify every feeder, every panel, and every subpanel. Confirm which exceptions, if any, you plan to rely on, and document the conditions. Note the disconnect locations and test for absence of voltage per NFPA 70E 120.6.

1. Identify all sources feeding the demolition zone, including backup generators, PV, and battery storage per 705.12
2. Open and lock out each source, apply tags with date, time, and qualified person's name
3. Verify dead with a properly rated meter, then test the meter on a known source
4. If relying on an exception, mark the boundary between demo zone and energized portion with barriers and signage
5. Communicate the plan to the GC and demo crew before mobilization

Field tip: photograph every panel directory and every disconnect label before demo starts. Half the time the directory is wrong, but the photo proves what you saw and when, which protects you if something energized shows up later.

When the Exception Does Not Apply

If the demo is total, the exceptions are irrelevant. Pull the meter, coordinate the utility, and remove the service per local POCO requirements. If the demo is partial but the energized feeder passes through the demo zone, you cannot use the partial-demo exception. Reroute the feeder first or shut it down for the duration.

Temporary power during demolition falls under Article 590, not 90.15. Once you energize a temp service or temp feeder, it has its own rules for GFCI protection per 590.6, disconnecting means per 590.4(H), and time limits per 590.3. Do not let a demo exception blur into a temp-power conversation.

When in doubt, default to disconnection. 90.15 was written because energized conductors in demo zones have killed people. The exceptions exist for legitimate phased work, not for schedule pressure.