insulation of a device in a metal box

[iwire]

Wrapping with tape, however, is a common spec for large commercial jobs.

So how much tape?

One wrap, two, ten?

 

[480sparky]

So how much tape?

One wrap, two, ten?

Last time I had that in a spec was three complete wraps. Scotch 33, no less.

They also required all metal conduit connectors to be bushed, and did not allow flex other than for troffers & motors.

Overkill? IMPO, yes. But if they want to pony up for it, all the more money for me, I say. Heck, if they wanted to pay me do dance a little Irish jig every day, I'd add that into the proposal as well.....:grin:

 

[Oakey]

Its not in the code. Your teacher is telling you the way he does it, just like my old teacher told us never twist the wires in a splice. 220-221 whatever...

 

[mthead]

insulation of a device in a metal box

The best thing about this thread -there are many different ways to do things and still achieve a safe installation--taping any device was an old time practise-started back when metal bx's were the norm and switches@recpts [those in use 40-50 years ago]had a wider profile--lets face facts;wrong or right most repair work is done live so you were making it easier for yourself were you to return to a job in the future to pull that device out witout inadvertently catching the side of the box and producing a brief lightshow .While that might not worry one of us [although it should if you were too familiar with that happening when you worked live] you can bet that grandma and her cat were not happy with that display of professionalism.
Anyway- never a requirement but a habit for some as they do their installations--nothing wrong with it.

 

[bkludecke]

I don't tape devices usually but there are some old type tight boxes w/alotta wire where a couple of wraps of tape makes things go quicker and easier.

I agree that it's a troubleshooter's thing. There are sometimes when I open up an old recept box (hot) I am amazed at the guy who was able to shoehorn all that into the box. Now I've got to put it all back in there plus maybe upgrade to a GFCI device or dimmer as well. But it pays well.

 

[peter d]

The company I used to work for wanted us to tape all devices, I almost never would and would not ask those under me to.

I also worked for the same company and I didn't tape devices either. That didn't go over well with some of the foremen (not Bob of course) but I would do it if asked to.

I don't see the point of it at all.

 

[chris kennedy]

I don't tape. Heres a tip for any youngsters out there.

If you tape a device and when pulling wire, break the last inch and twist it well between your fingers. This gives you (more importantly ME) a nice flag to grab to undo the tape.

 

[480sparky]

I don't tape. Heres a tip for any youngsters out there.

If you tape a device and when pulling wire, break the last inch and twist it well between your fingers. This gives you (more importantly ME) a nice flag to grab to undo the tape.

I call that a 'Buddy Cut".

 

[jerm]

Wrapping with tape, however, is a common spec for large commercial jobs.

We do primarily "large commercial jobs", some medium in there, no homes.

I've never seen a spec for tape. But I have seen the following, which I believe the architects do to increase the cost of the job and thus their percentage.

* steel fittings only, with interior bushings. (they cost about 4 times the usual stuff)
* nothing smaller than 3/4 EMT
* compression fittings only (indoors! cmmon!)

Jeremy
Tulsa, Ok

 

[peter d]

* steel fittings only, with interior bushings. (they cost about 4 times the usual stuff)
* nothing smaller than 3/4 EMT
* compression fittings only (indoors! cmmon!)

Steel is actually cheaper than die-cast fittings, and the insulated throat is nice for hardly any additional cost.

But I think a compression-only spec is ridiculous. I'll take a set-screw fitting over a compression any day.

 

[iwire]

I believe the thought is compression fittings provide a better ground fault path.

 

[480sparky]

We do primarily "large commercial jobs", some medium in there, no homes.

I've never seen a spec for tape. But I have seen the following, which I believe the architects do to increase the cost of the job and thus their percentage.

* steel fittings only, with interior bushings. (they cost about 4 times the usual stuff)
* nothing smaller than 3/4 EMT
* compression fittings only (indoors! cmmon!)

Jeremy
Tulsa, Ok

Steel fittings w/ int. bushings are standard specs for most large comm. jobs I've done, too, as well as 3/4" minimum.

They can spec whatever they want. I just add it to the proposal.... more money for me!

 

[peter d]

I believe the thought is compression fittings provide a better ground fault path.

Maybe they do. But I can't imagine the difference is all that great.

The worst part is that compression connectors can be hard to tighten in certain spots (like a rack full of them in a crowded ceiling in a science lab, for instance. ) so they may not get tightened at all.

 

[jerm]

Steel is actually cheaper than die-cast fittings, and the insulated throat is nice for hardly any additional cost.

Humm, not around here-- no one stocks them and they're special order.

Jeremy
Tulsa, Ok

 

[iwire]

Maybe they do. But I can't imagine the difference is all that great.

That is also my opinion.

Also any job spec that has a 'compression fitting only' requirement will likely have a copper EGC requirement.

 

[jerm]

Also any job spec that has a 'compression fitting only' requirement will likely have a copper EGC requirement.

We're used to that one- copper EGC is a *very* common spec on our large jobs. It confuses the apprentices when we go on the smaller jobs and stop pulling greens through emt...

"don't you want a green in there?"

"go read 358.60 and then you tell me!"

Jeremy
Tulsa, Ok

 

[jrannis]

in class our teacher has us cover the terminals of all switches and receptacles with electrical tape anytime their in a metallic box (like for drywall). i was wondering where in the NEC it says that you gotta insulate the exposed terminals of devices like switches and receptacles. lookin for the specific code section plz and explination if possible

Ive noticed this. It looks very un-professional, much like using and taping those hard plastic red wire nuts. Its a good sign that the handy man has reared his ulgy head again.

If your installation cannot provide clearance then the work should be corrected.

As for the insulated throat connectors,
BTW you can buy the plastic inserts seperately if you get into a spec jam.

Compression fitting indoors,
Im not a big fan of compression fittings either. Steel Set Screw are far superior as far as Im concerned. The only time I like compression fittings is if Im doing a demo on a job. All you have to do is turn the pipe a little bit and they come right apart...... so much for being a better ground!
If you remember the studies after the SF earth quake, the only fittings that were in tact, were steel set screw.

 

[LawnGuyLandSparky]

Same here - Installed correctly the receptical does not have enough play to hit the sides.

Lawn guy - why would the receptical be in prior to mud and paint without a cover plate?

Often the painters use spackle knives because there's "stuff" on the walls. Not every, in fact most jobs cannot go in the exact proper, ideal order. (I've seen fireproofing shot after sheetrock was up!)

Many times devices are installed prior to the 1st coat of mud. Often they're live because the temps have been rendered worthless due to the "closing in."

 

[LawnGuyLandSparky]

I don't tape. Heres a tip for any youngsters out there.

If you tape a device and when pulling wire, break the last inch and twist it well between your fingers. This gives you (more importantly ME) a nice flag to grab to undo the tape.

You mean "leave a tail?"

 

[iwire]

Many times devices are installed prior to the 1st coat of mud. Often they're live because the temps have been rendered worthless due to the "closing in."

You do understand that you could receive a OSHA fine for plate-less live devices?

It is also a NEC violation even during construction.