Box Fill

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byourdesky

byourdesky

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I was reading through article 314 and I am puzzled by what I read in there particularly the following..."Device or Equipment Fill For each yoke or strap containing one or more device a double volume allowance in accordance with table 314.16(b) shall be made"

I looked at table 314.16(b) and that is where my confusion lies....exactly how much volume does a switch or receptacle require?....thank you and please type slow because i read slow....thanks!!:)
 
You would count two conductors based on the size of the conductors connected to each device. So for example a switch with 2-#12 conductors attached to it would require a deduction equivalent to 2-#12 conductors or 2*2.25 cubic inches.
 
A 110V 20A circuit with one receptacle would be:
  1. 6.75 in sq (3 conductors, hot, neutral & equipment ground)
  2. 4.5 in sq (2 conductors for the device)
11.25 in sq total, I think most handy boxes are 10 cu in (3x2x2). In this example you would need a box larger than 11.25 cu in
 
tryinghard said:
A 110V 20A circuit with one receptacle would be:
  1. 6.75 in sq (3 conductors, hot, neutral & equipment ground)
  2. 4.5 in sq (2 conductors for the device)
11.25 in sq total, I think most handy boxes are 10 cu in (3x2x2). In this example you would need a box larger than 11.25 cu in
Click to expand...

Don't forget that some box connectors are also required to be counted if it's clamping mechanism is inside the box. A single volume allowance is needed for one or more connectors.

Also, only one volume allowance is required for any number of grounding conductors, i.e., if three grounding conductors are present, only a single volume allowance is required. In both of the above cases, the volume allowance must be calculated using the largest conductor in the box.

In addition, we don't need to count any conductor that both originates and ends in the same box.

And...*only* conduit bodies that are durably and legibly marked by the manufacturer with their volume shall be permitted to contain splices, taps or devices. Some electricians think that splices are not permitted in conduit bodies at all, but that is not the case. It's just not the best idea, of course....
 
K8MHZ said:
Don't forget that some box connectors are also required to be counted if it's clamping mechanism is inside the box. A single volume allowance is needed for one or more connectors...
Click to expand...

Yah howdy, :) I also understand the equipment ground has to be counted even if mechanical is the application.
My real point in using the handy box as example is to reveal that it is not big enough to include a device, I hate overfill in any box.
 
HaskinsElectric said:
Deleted message and continuing off topic conversation via PM
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Thank you. And I would use this as a reminder to the rest of us who want to chat about off topic things. Use the PM feature for that since most of us will have absolutely no idea what you're talking about.
 
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tryinghard said:
I also understand the equipment ground has to be counted even if mechanical is the application.
Click to expand...

HaskinsElectric said:
Are you saying you must count a wire that is not present?
Click to expand...

Yes as per 314-16(B)(5), see also 406-10 & 250-146. The only way around this is if the criteria of 250-146(A) through (D) are met and that is not likely if this same person is using a handy box.

When I stated mechanically grounded earlier I meant no EGC just conduit and fittings providing this like those listed in 250-118 (2)-(14)
 
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