Power and phone lines for the shop - meeting the NEC

[Nova]

A number of years ago the company I work for erected a small building approximately 250' from the road. When the telephone line was run the local phone company direct buried the phone wire. This spring a woodchuck ate through their cable. Now it's going to cost them dearly to rebury the cable (it still hasn't been done). Had they ran the wire in a conduit, it probably wouldn't have been damaged, and it would be a lot less costly to pull in a new wire if it became necessary.

-- Jack Novak Buffalo, NY - USA (Remove "SPAM" from email address to reply)

[Morgans]

You must have a separate, full sized neutral, and a ground. The neutral and ground must have separate busses, and the neutral buss must be separate and insulated from the case of the breaker housing. One of the busses is probably already insulated, and has to be grounded, if need be, with a separate thingies.

[Morgans]

It can be a smaller. I do

Wrongo. If it is the first panel, the neutral does not need to be as big as the hot conductors. When it is a sub panel, it has to have 3 full sized conductors, and a separate ground, separate busses on the second panel, neutral insulated.

It does not have to make sense to you. It is the code, remember?

[Morgans]

Don't bother The new code bears little resemblance to the current code.

[Morgans]

Gads, more bad advise. Elect. conduit is UV approved, and no problem. Use glue and have a first class setup.

[Erik Ahrens]

Actually, I just read it in the NEC a few days ago and now can't find where it was stated. When I find it (and my mind) I'll attempt to clarify.

Yes, you are right! I was thinking of running different voltages in the same conduit. My apologies.

[Bob Davis]

Thanks for the added note. I'm all for doing something that will outlast me. There are some practical considerations that I did not add. The conduit will be in the shade, anyway. My wife wants me to build a wood box around it to "hide it". And last but not least - I don't have the tools to thread conduit. Its one of those tools that I will never acquire.

Bob

[Bob Davis]

Got it. I bought one of the GE consumer main lug boxes and purchased a separate ground bus that bolts straight to the case.

Whew! Its a good thing my labor is free. I started down this quest because just adding branch breakers to my existing panel was so darned expensive (no-longer manufactured Federal Pacific). It was cheaper to add one big breaker in it to feed the subpanel. I like the idea of paying $8 for a dual

20 amp breaker instead of $48!

Bob

[B a r r y B u r k e J r .]

Not really true.

Most phone companies, and CATV, for that matter, now use a machine that slits the ground, places the cable, and folds the turf back in place. It's fast, easy and inexpensive, compared to installing conduit. The delay may involve an outside contractor's scheduling. My father waited 6 months for a cable TV wire to get reburied.

Based on the total number of buried service installations that go in, compared to those that go bad enough to be completely replaced, no conduit is much cheaper. If it wasn't, they'd install the conduit, just as they still do for large cables. Believe me, the phone company _is_ doing it the cheapest way possible overall, based on averages.

Barry

[Mark Jerde]

What?!?!? A *TOOL* not to acqurie??? Are you feeling ok?

-- Mark

[Mark]

Thanks Doug.

I thought I asked the inspector if it was permissible, I thought he said yes with 600 volt insulation.

I guess I should ask again.

I guess all those lighting conductors I ran in the conduit with communications conductors are now going to be low voltage operating relays.

[Bob G]

It has been well over 10 years ..closer to 20 I guess..since I built my shop ..and honestly I do remember I ran 4 a wire telephone line inside the 2 inch pvc line I ran to the shop (used indivifual 6 guage wire for the electrical )...

But I am curious as to why everyone said not to run the phone line inside the same pvc... Mine has been working just fine all these years.. ...

The phones Main use is honestly so my wife can call me for dinner... (used as an intercom)...

I do wish I had run a Cat 5 cable down to the shop also...BUT back then I had never heard of Cat 5 and a 300 baud dial up account was ok a 1200 baud dial up was "bitching fast"... But the wireless connection to a laptop does work...

Bob Griffiths

Bob GRiffiths

[Dennis M. O'Connor]

While the odds of a fault in the power-lines and phone-lines insulation might cause the phone wires to become "hot" (especially in the presence of water in the conduit, which happens) may be low, the NEC authorities probably think it isn't worth the risk.

The 100-amp 220V feed to our shop is in conduit, and the phone lines and alarm-system lines are 12" above it, in the same trench, in armored direct-burial cable. (As long as you are running cable, a few extra pairs for an alarm system is cheap enough, and may someday save your tools.)

[ranck]

The current NEC does not permit it, and I think that has been true for a long time, as long as I can remember, but *local* code does not always follow the NEC. And local inspectors may interpret the code differently than you might think. It almost never causes a problem to use a safer practice than the local inspector requires, but I would never try to convince him/her to let me squeak by on something.

I really hope you mean this.

Bill Ranck Blacksburg, Va.

[Bob Davis]

So how far away is your shop? Is it line of site? Wireless is amazing and they have wireless repeaters to amplify the signal that don't cost much. I'm placing a repeater between my (network) router and the shop and setting up a custom stand for my laptop. I work as a consultant and have to check email frequently waiting on jobs, so I might as well being working in the shop with easy access to email.

Bob

[Bob Davis]

What are you guys with 100 amp feeds doing in your shop?!!!!???? I can't buy enough tools to suck that much power, even if run at the same time. If my math is right, it would take 8 3 hp motors running loaded at the same time to approach loading it up. I sure don't want the electricity bill for that.

[Gfretwell]

Actually if you read 220.22 you only have to size the neutral to the "unbalanced load". If your sub panel is all 240v breakers with no neutral load you don't even need a neutral. As an inspector I would demand that the neutral was sized to the largest total number of single pole breakers on either phase. That could easily be bigger than the required size of the feeder "hots" though if this was a general lighting panel, loaded with single pole breakers so you default to "equal size". On the other hand if this is basically a 240v shop with a couple 120v circuits you could downsize the neutral. I still advise against it. The only logical reason you would do it would be a conduit fill issue with an already "in place" raceway system, you didn't want to dig up. Wire is cheap. The same is true with choosing a 3 wire feeder system over a 4 wire system. Lots of things that might work and may even be "hold your nose" legal are not the best choice.

[BRuce]

well lets see most shops are in the garage... a 3HP TS and a 2HP DC and the air compressor starts while they are both running and for some reason you have the lights on, the chest freezer starts, the wife opens the garage door... Thats not 100Amps not even 80Amps which is the max you should draw but the voltage drop on smaller conductors might cause issues. As another poster said "wire is cheap".

BRuce

Bob Davis wrote:

[Nova]

I work for a major telephone company and part of my job requires me to cover excavations that might affect our cables. I've been doing this now for over four years, covering an area encompassing the entire western third of New York state (from

20 miles east of Rochester, NY to the Pennsylvania border). Although I know these devices exist, I have never encountered any contractor using one.

-- Jack Novak Buffalo, NY - USA (Remove "SPAM" from email address to reply)

[Gfretwell]

I imagine you are working on the cables that run down the right of way. These machines are used to bury the customers drop in the yard. Around here they just use a spade and they barely get under the sod. I assume they are worried about hitting sprinkler pipes that are 4-6" down. I have one that popped up in my yard. I told the telco about it but they don't seem interested in fixing it until I run over it with the lawn mower.