How to calculate Auxiliary Gutter fill 366.22(A),(B)

Categories: Electrical Safety


Sizing a gutter for the proper fit is relatively easy.  I get a lot of calls to make sure that the gutter that they are using is up to code. 

We are allowed by code to fill a gutter to 20%. of its interior cross-sectional area (366.22(A),(B))  This is for both sheet metal and Nonmetallic gutters

Figuring the 20% is easy, for example.

If you have a 6 X 6 gutter, that would have total of 36 sq. in. and 20% of that is 7.2 sq. in. (36  X  20%  =  7.2 sq. in.) of space to use.  Table

5 is used for the area per conductor.  Take a 3/0 THWN conductor it is listed at .2679 sq. in.for each.  if you wanted to know how many could be

used in a 6  X  6 gutter, you can take the 7.2 sq. in. and   divide it by .2679 to get the maximum number that would be allowed to be installed in

that gutter.  7.2  /  .2679  =  26 conductors. 

You would also have to check the wire bending space minimum from Table 312.6(A). which would require a minimum of 4’” for a 3/0 conductor.


Till next time, work safe always check the circuit with a tester.


Categories: Code change of the week

With all the new electronic dimmers there seems to be a need for neutral conductors at switch locations.  This new code section in the 2011 NEC requires that if you cannot access a switch box after the installation then a neutral conductors is required to be installed in the box.  If you can access the box after the installation then the neutral will not be required until it is needed.

This is a 2011 code change and will not affect installation being done now but when it is adopted this will be something all the inspectors will be looking for.

Until next week

Be safe, always check to see if it is hot.




Categories: Uncategorized

Until now you had to use a  2 pole breaker for a circuit with a common neutral.  GE now has given us a way to do the same thing with 2 single pole breakers using a handle tie instead.  Check out the attached PDF and see how you can protect a common neutral circuit without buying a 2 pole Arc Fault breaker.  Make sure you look at the diagram which shows how to wire the circuits using 2 single pole breakers instead of a 2pole Arc Fault breaker.  I can’t figure out how we did not know about this before it was published back in 2009?


Combination Arc Fault Circuit Interrupter – Selection and Application Guidelines and Technical|DET-719|generic

To get this to work you have to type in DET-719 at the GE site.

That it for this week.



Outlet boxes for ceiling fans 314.27 (C) 2011 NEC

Categories: Uncategorized

When installing a ceiling box that may be used for a fan, and you install a spare switch leg to that box. Such as 14/3 or 12/3 NM cable, the box shall be listed for support of a fan.  This requirement only applies to single and multi-family dwellings.  The code panel recognized that home owners and/or renters sometimes change out the light fixture and put a fan in its place.  So this requirement will help when this activity is done in a single or multi-family dwelling unit.

110.26 (F) Locked Electrical Equipment Rooms or Enclosures.

Categories: Uncategorized

(F) Locked Electrical Equipment Rooms or Enclosures.
Electrical equipment rooms or enclosures housing electrical
apparatus that are controlled by a lock(s) shall be considered
accessible to qualified persons.


The breaker that is mount in a generator enclosure will be considered in compliance with this section only when it has a lock that is controlled with a key, and not an Allen wrench.   When the section was written it did not include an Allen wrench in the standard so it is not part of the code section.

So long as it is controlled by a key it will be incompliance with this section.

Multi-wire branch circuits

Categories: Code change of the week

When sharing the Neutral of a multi-wire branch circuit, the circuit breaker has to be common trip.

Single phase, Three phase circuits now require a 2 pole or three pole circuit breaker.


Online Registration

Categories: News & Stuff

Online registration for our classes will be here soon. With this new system you will be able to register, reserve, and pay for your seat all from the comfort of your home or office. Please check back soon.