[dennypower]

Well I spent all my money building a new detached garage in my backyard. Of course I pulled the permit myself and trusted some of the concerns to be dealt with by subs. I had the plumber run me an under ground line for the power when they ran the sewer to the garage.

Anyway the line was only big enough to run a 6-3 line white red black and a ground. It runs a total of 120' ft to the garage. The plan is for a workshop and a small apartment above. As its set up now, its hooked to the main panel on the outside of the house with a 50 amp fuse.

What if any thing can I do to manage all the things I would need/want for a garage workshop and apartment ie- small range, small elect. Water heater, maybe an occasional 240v welding.

PLEASE someone give me hope! Thanks

[stanfortyman]

Why are you running cable in conduit?? 6/3UF is HUGE!

What size and type is the conduit?

[dennypower]

Well Im going to really sound like a idoit but, I'm not sure what it is. There is a thick blue plastic tube that was run underground when they ran the sewer. The tube is a little bigger than an one inch. I was able to push the 6-3 through it. With a little bit of room. Don't think this is even conduit but more of a tube for conveinance.

Now that I sound really stupid, what you think?

[stanfortyman]

I think that is the WRONG conduit for this application.

WHY (! ) did you have a plumber run a conduit for electrical??

1"?? Was this 6/3 cable black and round? Or was it grey and flat?

[dennypower]

6/3 is black and round- thick stuff paid $200 for 120ft

[stanfortyman]

And no one told you that stuff was completely illegal for use underground, even in conduit??

[Credendovidis]

And no one told you that stuff was completely illegal for use underground, even in conduit???

Not completely true...
UF cable may be direct buried without being put into any pipe. So the installed thick blue plastic tube should be seen as protection against roots or garden activities. Not as conduit.
So it is not illegal.
.
6/3 UF is made for 55 Amps capacity
.
The real problem is that 6/3 UF cable is below official specification.
At 55 Amps for cable length beyond 90 feet 4/0 wiring is required.
.
;)

[stanfortyman]

Not completely true ....

YES SIR, it is COMPLETELY true.

The black round 6/3NM cable is NOT UF, it is NM-B. NM-B CANNOT be used outdoors where subject to moisture and certainly NOT underground, EVEN in conduit.

[stanfortyman]

The real problem is that 6/3 UF cable is below official specification.

PLEASE show me this "official specification" you speak of.

At 55 Amps for cable length beyond 90 feet 4/0 wiring is required.

It REALLY is time you lose that 12v voltage drop chart you are using and forget that you would need anything even close to 4/0 for such a circuit.

[KISS]

For a 5% drop at 55A, I get 111 feet for #6 copper wire.
For a feed, I think you want 3%.
Breaker is rated for 50A.
Continuous permissible current would be 0.8*50 = 40 Amps.
With 40A, I get 90 feet for #6 for a 2.9% drop.

Credendovidis:
Stanfortyman doesn't believe in using 120V. He wants to use 240V. I showed him a reference that 120V must be used and it was a page from a license study guide.So, he has his opinion and we have ours. I'm not sure what's required to change it. He doesn't even respect tkrussell's response either. I think we need to find it in the code somewhere or ask God for it.

[stanfortyman]

"Continous permissable current" is not an issue with a feeder. Here is the text from 215.2(A)(1):
"The minimum feeder-circuit conductor size, before the application of any adjustment or correction factors, shall have an allowable ampacity not less than the noncontinuous load plus 125 percent of the continuous load."

Almost nothing in a residence is considered a continuous load, so the 125% does not even really apply.
Do you also agree that the poster needs to use 4/0 conductors?? Come on. Be real.

Besides, voltage drop is NOT the issue here, it is NM-B (romex) in an underground outside conduit.
Do you at least agree that that is highly illegal and not safe (long term)??
And also that the installed used plumbing pipe for the feeder? How about that?






"He doesn't even respect tkrussell's response either."
So by not agreeing with something that is equated to disrespect?? What kind of logic is that.

What is with this place?? If you disagree with the king pins you get ostracized? That's fine, I like playing that game.
I never was much for popularity contests, and I DO NOT mind being the unpopular one, as long as my advice is sound.

TK is not god either. I have seen some pretty ambiguous informations given my him. NO ONE is infallible. I make mistakes too.

If I see misinformation on an electrical DIY message board you can bet I will try and correct that information the best I can, and not just with opinion.
There is too much at stake not to!

[KISS]

Right nm-b doesn't belong in conduit. It should not have passed inspection, but we don't know if it was inspected yet. There is speculation that nm-b cable was run which seems like a good speculation.

The NM-B need to be removed.

I looked over the posts and I see no reference to the type op pipe/conduit. I see only a reference that a plumber did it.

All I did is compute the continuous load with a 3% voltage drop, Do I know it's continuous. No. Do I know the loads. No.

There is a water heater, welder and small stove. Are any continuous. No, but the water heater has a mind all it's own and omes on when it wants to.

All the loads on at the same time can't exceed 50 A. Breaker pops.

Sizing the wire at 0.8 * (breaker size) with a max 3% drop seems like the right way to go without knowing the loads.

The design is being approaced bassackwards,

Loads (continuous & non-continuous), probably all non-continuous.
Largest (sum of loads) on a the same time.
Wire size and breaker size
Conduit size

It's also a case if "If you can't find the time to do it right, when are you going to find the time to do it over".

The NM-B cable has to go. Need a better handle of the anticipated loads and start over.