[rpoz-29]

I want to relocate my welder, and compressor to my detached garage. I had an electrician give me a price, and I just wanted to see if it seems reasonable. The garage is about 75 feet from the house. He's going to supply all the parts, (wire, outlets, junction boxes, breakers, etc. for a 60 amp service), for around $800.00. He said that the cost of wire has sky-rocketed,(and I don't doubt it with the prices I've seen for scrap metal), but does his price seem reasonable? Thanks!

[nape]

That's a steal if he's running rigid underground, if he's running PVC, it's still a deal.

Mitch, he could get away with #3 for a 60A service though. The conductors max continuous load should be spec'd to <=80% of max rating. #3 is rated at 75A, so it fits the bill.

Bill, if you ever plan to upgrade the service you might want to look at having him run bigger wire, but 60A for just large tools should be plenty since it sounds like the branch circuits are on a different service. I'd move ASAP if the quote is that low because wire prices change everyday.

This post has been edited by nape: Nov 5 2006, 08:45 PM

[mitchntx]

Mitch, he could get away with #3 for a 60A service though. The conductors max continuous load should be spec'd to <=80% of max rating. #3 is rated at 75A, so it fits the bill.

For a 75' run? (IMG:http://www.frrax.com/rrforum/style_emoticons/default/huh.gif) You're the sparky! (IMG:http://www.frrax.com/rrforum/style_emoticons/default/beerchug.gif)

[nape]

Mitch, he could get away with #3 for a 60A service though. The conductors max continuous load should be spec'd to <=80% of max rating. #3 is rated at 75A, so it fits the bill.

For a 75' run? (IMG:http://www.frrax.com/rrforum/style_emoticons/default/huh.gif) You're the sparky! (IMG:http://www.frrax.com/rrforum/style_emoticons/default/beerchug.gif)

From the 2005 National Code Book, #3 has a resistance of .245 ohms/1000'.

To figure voltage drop:

delta V = I * R
delta V = 60A * (.245 ohms/1000' * 150')
delta V = 2.2V

Maximum voltage drop is 5% (12V) of source voltage (240V).

While I was digging up the info, I ran across the table for services. I believe the ratings are higher since it is usually unlikely that everything in the panel will be on and at full draw.

Table 310.15((IMG:http://www.frrax.com/rrforum/style_emoticons/default/cool.gif) (6) - Conductor Type and Sizes for 120/240-Volt, 3-Wire, Single-Phase Dwelling Services and Feeders. (Copper cable listed only)

4 - 100A
3 - 110A
2 - 125A
1 - 150A

1/0 - 175A
2/0 - 200A
3/0 - 225A
4/0 - 250A

250kcm - 300A
350kcm - 350A
400kcm - 400A

I guess C-C.com is wearing off on me about bringing the tech...

edit- to fix the calc.

This post has been edited by nape: Nov 7 2006, 02:21 AM