Residential Wiring - NM Cables in Fiberglass Boxes Without Clamps

Don't know about what's allowed and what's not the code, but in the absence of any other clamps (and assuming it's round cable) I'd be inclined to use nylon cable glands (with suitable flammability rating) for peace of mind.

I should talk to the inspector and compare your "common sense" with what he accepts. Metal boxes have been replaced by plastic in developed countries since decades. You can also go the long way to have it changed in the code and find out how administration works.

Not sure your location but some cities have there own codes in addition to NEC.

The box you mention is very common. Normally it is required to use cable staples, most inspectors require them to be around 6" from where the cable enters the box. There are different types of staples; steel or plastic with small nails on both sides. They come an many different sizes for different cables. Keep in mind to staple the cables in the middle of the stud not twards the front or back. If the guy doing the sheet rock missed the stud and wire is not in the center of the stud he could put a screw in it, not good. I think the plastic staples work best. Steel staples you can get too tight and cut in to the cable insulation. It's alwas a good idea to talk to your inspector, it may save a lot of rework.

Good evening. I love this thread being a electrician myself. I dont think I need to say anything more. Do you have a picture of these "fiberglass" boxes..... Lol to be honest i dont think i have ever seen one.... all i know of is metal and PVC based boxes....

And ask the inspector, he is your friend....... most of the time. lol

Oh and yeah I have heard both sides of Metal Based spiked clips and plastic 2 nail clips. I think both have their advantages. Remember that the metal spike has a lip to tell you when to stop hammering. lol. But at the same time the plastic clips dont work at all on armoured cable which i see some peoplle instasll in their home.

Oh and I have another question to ask. In southern ontario everyone uses 30-30s... a PVC based connector for romex cable to enter a panel or a junction via a knockout (1/2"). While everyone in a city in northern ontario uses metal 1/2" connectors... which dont like to much bc it can be overtightened and doesnt breath along with the cable

Regardless of what people use, heres something i see people do over and over ... Stop using a power drill, even cordless on any electrical device... from the panel to receptacles to lights, etc.... they cause more damaged then they safe time and convience......

Oh and remember code is minimum! You are building a home! Make it the one that last the longest on the street.

I think you've got it right and the extra charge for having the inspector preview the work is like money well spent especially when you are unsure.

Check this also for added safety:

Soldering is allowed by the NEC - IF the connection is *mechanically* and electrically secure *before* the solder is applied (Section 110.14(B).)

Conductors shall be spliced or joined with splicing devices identified for the use OR by brazing,welding,or soldering with a fusible metal alloy.Soldered splices shall first be spliced or joined so as to be MECHANICALLY and electrically secure without solder and then soldered.

Un-clamped PVC or Fiberglass (Nonmetalic) boxes are common for residential wiring. See NEC 310.17 (C) Exception. I am surprised the contractor elected to use fiberglass boxes, since PVC is less expensive. The electrical inspector should inspect the wiring before the walls are covered (the ruff in inspection), if he sees anything wrong, he will point it out.

Agree with Old Goat.

Get the wiring inspected before the walls are covered.

I checked and finally figured out what a fiberglass junction box is. We call them semi-metal bc they have some qualities of metal and PVC boxes....

My questions is why would someone use Fiberglass boxes and what are their advances over metal boxes for inside applications and PVC boxes for outside weather exsposed applications.

A bird in the hand is worth two in the bush...maybe it's what they had on hand...

Thanks to all for your thoughts and observations. PWR2THEPEOPLE is right on target.

Please allow me to clarify:

I am obviously a do-it-yourselfer. I've done wiring on our farm buildings and only with metal boxes and conduit. I chose the fiberglass boxes because as I was looking through what was available at our local building supply store and I saw basically three options. I liked the fiberglass boxes because they were less expensive than metal boxes and I liked the look of them better than the blue plastic boxes (not very scientific).

I plan to contact the inspector as soon as possible to make sure I'm not doing something he doesn't like.

Thanks again

When it comes to farming. You should keep everything PVC. From what I have seen is that barns arent very water tight to begin with and especially animal waste., pesticides, chemicals eat up metal boxes and conduit like paper.....

We have done a few meat shops over the years and "meat plants".... everything was rigid pipe and within about 3-5 years the pipe would rust right through due to the chemicals they use for cleaning, etc. A little off topic but found it very intresting. Kept me employed.