National Electrical Code Articles and Information
National Electrical Code Top Ten Tips: Article 225 -- Outside Branch Circuits and Feeders
Based on the 2020 NEC
by Mark Lamendola
Please note, we do quote from copyrighted material. While the NFPA
does allow such quotes, it does so only for the purposes of education
regarding the National Electrical Code. This article is not a substitute
for the NEC.
These are the 10 NEC Article 225 items we deem most important, based
on the pervasiveness of confusion and the potential costs of same.
- Read the scope carefully. In many instances of
disagreement with the electrical inspector, folks are misapplying
- Table 225.3 clearly shows were other NEC Articles apply to
specific equipment and conductors.
- Overhead conductors outdoors must be insulated or covered (per
Article 100, a covering is not insulation) when within 10 feet of a
building—except as stated [225.4].
- 225.7 gives various rules for outdoor lighting. Note, there
are clearances established for circuits exceeding 120V.
- 225.14 provides the rules for open conductor spacing. For
example, "Open conductors shall be separated from open
conductors of other circuits or systems by not less than 100 mm (4
- 225.18 is "Clearance for Overhead Conductors and Cables." This has often
been a source of contention in court. It’s best to exceed the
requirement by a foot or two, as design and installation are two
different things and being off by an inch can burn you, despite the
fact that it’s substantial compliance and obviously satisfies the
intent of the Code. For one thing, a crane operator won’t know you
are an inch low, and that can get somebody killed. These are minimal
heights. Pay attention to the type of area a cable will pass over,
and use the highest clearance if in doubt. Also, create a clear path
for fire ladder equipment and other emergency apparatus. Sometimes, simply locating the overhead conductors at the same height but 15 feet to the east (or wherever) reduces danger by orders of magnitude. Can you route to the backside of the building and avoid the (for example, walkway) altogether? Meeting clearance requirements doesn't ensure nobody will get electrocuted. Use a combination of measures, wherever possible.
- 225.19 gives the clearances from buildings (1000V or less) —the comments we
gave for 225.18 also apply here.
- 225.34 addresses the grouping of disconnects. You can have a
single disconnect on a service. But, if you have more than one, you
must group all of them (except a fire pump disconnect, which has
special requirements). You can have a maximum of 6 disconnects per
- 225.37 covers an issue most installers routinely ignore or
inadequately comply with. You must have a circuit directory or
plaque (with some exceptions noted) to identify the circuits. The
intent here is not to have vague text, but to clearly identify the
circuits. This isn’t just for the convenience of the owner. It’s
also for the use of the first responders (e.g., for stopping an
electrocution), fire department workers and other emergency workers.
It is illegal to shirk responsibility here, and this particular
violation can carry heavy personal penalties for all concerned. Some of the new products on the market make this job much easier and the outcome much better. Check with your panel supplier to see what's available.
- 225.60 and 225.61 provide more information on clearances,
such as those over sidewalks.