adding power to the shop

[shop_hermit]

I would appreciate some advise on the size of power cable I should run to a shop. The distance from the main house panel to the shop (cable length) will be about 160 ft. I want to run aluminum feed cable for a new 100 amp panel in the shop. The cable will be buried and in 2 inch pvc conduit. I expect that with a small heatpump, running table saws, a fan and a dust collector vacuum, other tools, welder and lighting, I may pull on a regular basis up to 65 amps.

I was thinking of using 1/0-1/0-1/0-2 AL service feed for the 160 ft.

Is this overkill or not good enough?

Thanks.

 

[MagKarl]

I'm just a little bit ahead of you. My run is almost 200' and also 100A, ran 1/0 Al individual wires for hots and neutral, #4 for ground.

 

[alfredeneuman]

for 100 Amp sub-panel

4 ga. ( #4 ) alum & #6 ground

OR

3 ga ( #3 ) copper & #8 ground.

You need a minimum #1 Aluminum for 100 Amp anything

 

[nehog]

for 100 Amp sub-panel

4 ga. ( #4 ) alum & #6 ground

OR

3 ga ( #3 ) copper & #8 ground.

That al number is wrong.

 

[My Old Tools]

Drop it to 90 amps feeding a 100 amp panel and you can run mobile home feeder 2-2-2-4.

 

[DC73]

While you could get by with a smaller wire, I think 1/0 aluminum is a good choice for that run. Sometimes its not just about ampacity, you also have to consider voltage drop and possible future upgrades.

DC

 

[Norcal]

for 100 Amp sub-panel

4 ga. ( #4 ) alum & #6 ground

OR

3 ga ( #3 ) copper & #8 ground.

This is not correct even 4 AWG copper is too small.

 

[Aceman]

I would appreciate some advise on the size of power cable I should run to a shop. The distance from the main house panel to the shop (cable length) will be about 160 ft. I want to run aluminum feed cable for a new 100 amp panel in the shop. The cable will be buried and in 2 inch pvc conduit. I expect that with a small heatpump, running table saws, a fan and a dust collector vacuum, other tools, welder and lighting, I may pull on a regular basis up to 65 amps.

I was thinking of using 1/0-1/0-1/0-2 AL service feed for the 160 ft.

Is this overkill or not good enough?

Thanks.

That should work fine for the loads you have listed. Just make sure the cable has a RHH, RHW, etc rating on it. Without that rating it must stay outside the building.

Also, make sure you buy a pretty good sized panel to handle that cable. You don't want some little 100 amp 12 space panel that you have to stuff all that wiring into. If it was mine, I'd buy a 200 amp main breaker 30/40 panel, they are a dime a dozen and it will give you loads of room for your feeder cable as well as all the circuits you will ever put in it.

The 200 amp main breaker simply becomes a disconnect for your building, since you would only be feeding it with 100 amps.

 

[Norcal]

what qualifies you to refute basic electrical design?

for 200 amps you need 3/0 copper or 4/0 Alum.

100 amps is just fine with #3 copper or #4 alum.

assuming your are using THHN cable and CONDUIT.

I do this for a living... how about you ?!

Scary just plain scary if you not know that you cannot use the ninty degree column for sizing conductors, that is the type of advice you get at Home Depot.

 

[alfredeneuman]

what qualifies you to refute basic electrical design?

for 200 amps you need 3/0 copper or 4/0 Alum.

100 amps is just fine with #3 copper or #4 alum.

assuming your are using THHN cable and CONDUIT.

I do this for a living... how about you ?!

I know for a fact NorCal does this for a living.
I know for a fact that you either are delusional or severely misinformed.

Check the tables in the NEC and get back to us.
It's 310.15 (B)(16) in case you don't already know.

#4 Aluminum is only good for 65 Amps

EDIT:
I think you're using the Table for FREE AIR, not in CONDUIT. (in (17) not (16))

You really ought to consider a career change

 

[nehog]

I know for a fact NorCal does this for a living.
I know for a fact that you either are delusional or severely misinformed.

Check the tables in the NEC and get back to us.
It's 310.15 (B)(16) in case you don't already know.

#4 Aluminum is only good for 65 Amps

EDIT:
I think you're using the Table for FREE AIR, not in CONDUIT. (in (17) not (16))

You really ought to consider a career change

This is the correct answer. I may not do this for a living anymore, but I did. Saying 3 AWG Cu and 4 AWG Al can carry 100 amps is wrong for Al.

 

[Norcal]

Since when does rigid conduit buried underground get hotter than 90 degrees ?
Do you live in the SAHARA ?

go play with your romex, and plastic boxes little boy.

Real men use PIPE lol

Show me a 100 amp panel that will even accept a wire larger than #4 on the main lugs main breaker or neutral bus?


Get you nose out of the code book and try doing some actual work before you shoot off mouth.

No equipment is rated to use 90 degree conductors used at the 90 degree rating, they have to be used at the 60/75 degree rating. The only legitimate use of the 90 degree column is when derating.

You need to look at lug rating of panels, unless you only play with 2 space load centers the lugs will accept larger then 4 AWG.

 

[Aceman]

JACDes, you are missing 110.14(C)1.

 

[alfredeneuman]

I would suggest you learn how to read a code book.

The ampacity rating is based on the wire insulation you plan to use.

The wire insulation dictates the temperature rating you use
So yes because THHN cable is rated for 90 degrees C. and I am using only 3 current carrying conductors buried in a raceway ( rigid conduit) underground. I can use that column.

So per the chart using THHN cable "which is in the 90 degree column" #3 copper is good for 115 amps #4 alum 95 amps which is close enough.

Table 310.15(B)(16) - Highlighted

but like I said I know how to read... a pretty fundamental skill if you ask me.

This is perfectly acceptable for a SUB PANEL.

Main service (aka service entrance) is not a sub-panel.
This is another topic and unrelated to this subject.

For Service entrance wiring you use table 310.15.b.7
but as I said this is sub-panel not a service entrance...

Try re-reading your code book and get back to me.

YOU ARE WELCOME

:tard:


The lugs on the equipment dictate what temperature column you use.
There are no circuit breakers, panelboards, or the like with the lugs rated over 75°C. Some old circuit breakers and A/C units are even marked at 60°C.

"So per the chart using THHN cable "which is in the 90 degree column" #3 copper is good for 115 amps #4 alum 95 amps which is close enough"
The same chart in my (2011NEC) lists #3 Cu for 115 amps in the 90° column, and 75 amps for #4 Aluminum not 95

I'm glad NorCal quoted your post before you edited it. You should have left it as is. It was a lot more humorous that way.

 

[alfredeneuman]

I am a licensed professional.. how about you?!

I'm a licensed Electrical Contractor, having spent the last 40+ years doing mostly commercial and industrial work.

That has nothing to do with the fact that #4 aluminum has only a 75 (NOT 95) Amp rating in the 90° column, which is what you claimed.

The 95 Amp @ 90° rating is for #4 copper, NOT aluminum

 

[pattenp]

Uh... what happened to the posts that JACDes made? I was finding this to be entertaining.

 

[shop_hermit]

I really do appreciate everyones opinion.

However, I do not intend to use #4 or #6 wire for the feed to my sub-panel.
The very smallest wire I would consider is #2 and because of the length of run I have, I feel it may be undersized.

Below please find my original request so that the answers may be back on track.

Thank you all.

I would appreciate some advise on the size of power cable I should run to a shop. The distance from the main house panel to the shop (cable length) will be about 160 ft. I want to run aluminum feed cable for a new 100 amp panel in the shop. The cable will be buried and in 2 inch pvc conduit. I expect that with a small heatpump, running table saws, a fan and a dust collector vacuum, other tools, welder and lighting, I may pull on a regular basis up to 65 amps.

I was thinking of using 1/0-1/0-1/0-2 AL service feed for the 160 ft.

Is this overkill or not good enough?

Thanks.

 

[OccupantRJ]

Uh... what happened to the posts that JACDes made? I was finding this to be entertaining.

The force was STRONG in that one.......

 

[pattenp]

I really do appreciate everyones opinion.

However, I do not intend to use #4 or #6 wire for the feed to my sub-panel.
The very smallest wire I would consider is #2 and because of the length of run I have, I feel it may be undersized.

Below please find my original request so that the answers may be back on track.

Thank you all.

I would appreciate some advise on the size of power cable I should run to a shop. The distance from the main house panel to the shop (cable length) will be about 160 ft. I want to run aluminum feed cable for a new 100 amp panel in the shop. The cable will be buried and in 2 inch pvc conduit. I expect that with a small heatpump, running table saws, a fan and a dust collector vacuum, other tools, welder and lighting, I may pull on a regular basis up to 65 amps.

I was thinking of using 1/0-1/0-1/0-2 AL service feed for the 160 ft.

Is this overkill or not good enough?

Thanks.

I'd run 2/0-2/0-2/0-1 aluminum Mobile Home Feeder. The 2/0 is a standard size and will give you plenty of wiggle room with minimal voltage drop. It may also be the cheapest wire since it's a preassembled cable. The 2/0 should be the max size that will fit in a 100A breaker.

 

[alfredeneuman]

By Southwire's Voltage Drop Calculator at that length with a maximum voltage drop of 3% you'd need

a #2 aluminum conductor just to run the 65 Amps you have planned.
a 1/0 to run the entire 100 Amp load.

http://www.southwire.com/support/voltage-drop-calculator.htm

 

[nehog]

Uh... what happened to the posts that JACDes made? I was finding this to be entertaining.

When one finds themselves wrong...