Electrical upgrade advice/thoughts

[Abe Music]

Hey folks, hoping to get some opinions on something I'm wanting to do.

We recently moved to our new house and I finally have my very own detached garage / workshop!! YAY...unfortunately, the existing panel is being fed by a 25A breaker from the attached garage panel and is not acceptable for the machinery I have. After poking around on my own and having one electric company come out, it looks like the existing cable (romex 10 gauge oddly) is being run underground through 1.25" conduit and pops up in the wall of the detached garage. There's been no attempt yet to remove existing cable to know if it's possible to pull it out and run new through it, but I'm optimistic that I can get appropriate cable pulled for at least 60 amps and maybe more. I'll go as high as possible on the amps. I also want to put an appropriate surface mount panel and will run my own EMT and cable inside for outlets.

Oh, the distance from main panel in attached garage to new panel is approximately 70 feet (6 feet down + 55 feet across + 6 feet up + extra for bends.)

So, some questions I have:

1) Does this sound reasonable for what I want and trying to achieve?

2) Is there anything I'm missing or should be thinking about with this?

3) Assuming it is possible to do this, does a quote of $1827 sound like I'm getting ripped off?

The quote is really bothering me. It sounds terribly high and my reasoning is a quick estimate of materials that I could go buy at the borg:

70 feet x 4 conductor x 1.19/ft = $333.20 (I know ground is different, but keeping it easy and it pads the price a bit)

surface mount box = $150 (probably way cheaper, but padding price)

= $483.20

+ let's add 25% just in case = $604.00

Assuming that's even remotely close (which should be way high), that leaves about $1200 in labor and assuming $100 hourly rate, we're looking at 12 man hours of work? I just don't buy that and sounds like I'm getting ripped off. Would really like to know the opinions of others that have more knowledge about this stuff, but also don't want to get shafted and pay wayyyy more than need be. I have two other companies coming out this week to quote me too, so I'll soon find out what I'm getting into.

PS. The actual wording in the quote: "Tear out old 10/3 feeding detatched garage and running a new 100 amp line through existing conduit. Taking out 4 circuit disconnect and installing a 100 amp 20 circuit panel and tie back in existing circuits. Total investment would be $1827.00 with discount."

[Mike Cozad]

I'd say its fairly reasonable. I just rewired 130 year old farmhouse and spent what would equate to what you are on the garage panel I had replaced. To really know you should ask for an itemized quote. You can then negotiate if you think something is outside what would be considered reasonable.

[Frank Pratt]

You're not getting "ripped off". You've received an offer to do work requested at a price the vendor is willing to do it for. You can accept or reject that offer.

The quote does seem reasonable though.

[Julie Moriarty]

Based on your post, I would feel more comfortable if the description of the work being performed read something like this:


Secure permit (you or them)
Remove existing wiring between house main panel and garage panel.
Supply and install (4) #3 AWG conductors in existing 1-1/4" conduit
Supply and install 100A, 120/240, 20 space main breaker panel (should include a list of what, if any, branch circuit breakers that will be supplied)
Reconnect all existing loads.
Terminate wiring and test. (I would want confirmation the grounding is properly installed too.)
Call Electrical inspector and obtain approval.


If the romex comes out easily and there are no surprises, this is a fairly easy job. Two guys could have it done in a few hours.

If the romex is stuck, or if the conduit needs to be cleaned out, or if there are modifications that need to be made to install the new panel, etc, the labor hours could double or triple. The big unknown is the condition of the conduit and the wire in it. I've had 3/4" GRC under a concrete slab with (3) #12 wires that broke trying to remove them. We had to install new conduit overhead.

[Kevin Goss]

As long as the old wires pull out the price is high. That's the price of a new 200 amp service pretty much. Get a few other quotes and see where you're at. You may have just gotten a high quote from a busy guy who doesn't really want the work unless he's making good money. In any case it can't hurt to ask around for prices. It's a pretty straightforward easy job.

[Jim Andrew]

Is this house in the city of Nashville, or nearby? Check with the building services office to see if you are allowed to do this work yourself. There are electricians who can advise you. Personally, I would turn the power off, then disconnect the wire and see if you can move it. Then buy a piece of replacement wire and attach it to the end of the old wire and pull it through the conduit.
I wired my entire shop with advise of a neighbor who is an electrician. Here you are allowed to do your own work on your own property.

[Paul F Franklin]

Since building is detached it will need 2 ground rods installed as well.

[Erik Manchester]

Abe,

I would say that you have a fair quote there, but I would specify the terms as Julie as suggested.

Having pulled some cable before, I can assure you that pulling 70' of #3 through 1.25" conduit of unknown condition will be quite a challenge and odds are high that you may end up digging.

This may be why the original offer seems high, as the contractor wants to be certain he is not going to lose money if he has to dig up the conduit.

[Charles Taylor]

Since building is detached it will need 2 ground rods installed as well.
Get a second, local opinion. I have a detached workshop with 100A service, and it is not separately grounded.

[Robert Engel]

Hard to say rates vary by location.

Get a couple more quotes and ask some of the specifics mentioned here.

IMO you don't need a 100A service for a garage shop.

I ran my whole shop off a 60A feed for 20 years with no problems.

[John K Jordan]

Oh, the distance from main panel in attached garage to new panel is approximately 70 feet (6 feet down + 55 feet across + 6 feet up + extra for bends.)


If you discover the old wires cannot even be pulled out and decide to dig, consider putting in a spare conduit. I dug 250 ft to feed 100 amps to my shop (#1 awg copper). I put in a spare, empty 2" conduit with a rope inside for future use. I also ran a smaller conduit with Cat-5 cable for ethernet. Broadband ethernet can provide clean cell coverage and a good WiFi signal is great in the shop for internet, security system, and instructional youtube videos!

I have a backhoe so digging was easy but I've also rented trenchers to dig maybe 1500 ft for various power runs here on the farm. Of course if you have concrete in the way it's either more work or detours or power poles (yuck).

JKJ

(also I see someone mentioned not grounding the detached building separately. I am not a licensed electrician but before doing this you might want to check with your inspector - around here it is 4 wire feed, unbonded neutral in sub-panel, and separate ground rods.)

[Matt Marsh]

Get a second, local opinion. I have a detached workshop with 100A service, and it is not separately grounded.


It doesn't matter. A separate building is required to have it's own grounding electrode system. The only exception is when the separate building is fed by a single branch circuit. (2014 NEC 250.32 (A))

[Charles Taylor]

It doesn't matter. A separate building is required to have it's own grounding electrode system. The only exception is when the separate building is fed by a single branch circuit. (2014 NEC 250.32 (A))


Is that not the case here?

[Matt Marsh]

Is that not the case here?

I'm not real sure what you're asking Charles, but I believe his intent is to install a new 60 amp feeder to a new breaker panel, located in his separate structure. If that is indeed the case, then it would require a separate grounding electrode system installed according to article 250.32(A), and part III of article 250 of the NEC.

[Charles Taylor]

I'm not real sure what you're asking Charles...

Very well. If I'm not adding clarity to the discussion, then I should politely excuse myself. Best regards.

[jack duren]

I'm not real sure what you're asking Charles, but I believe his intent is to install a new 60 amp feeder to a new breaker panel, located in his separate structure. If that is indeed the case, then it would require a separate grounding electrode system installed according to article 250.32(A), and part III of article 250 of the NEC.

I assume he's feeding off the original panel from the source which is already grounded. If this is the case he's already grounded.

[David Castor]

If this is the case he's already grounded.

That may be, but the current NEC (250.32) requires "buildings or structures supplied by feeder or branch circuit to have a grounding electrode. As noted previously, there is an exception for a building fed by a single branch circuit. But if a sub-panel is to be installed in the shop building, that exception doesn't apply. A ground rod is needed to meet the current NEC. This was not always the case, but has been a requirement for a number of years, IIRC.

The price seems a little on the high side, but not excessively so. You may want to get another quote.

[Matt Marsh]

I assume he's feeding off the original panel from the source which is already grounded. If this is the case he's already grounded.

Any separate building/structure requires it's own grounding electrode system. The existing grounding electrode system at the structure where the feeders originate will not satisfy the requirements of article 250.32(A) for the separate structure. Again, the only exception is when that building/structure is fed with a single branch circuit (including a single multiwire branch circuit). In this case the exception does not qualify, because it is not being fed by a single branch circuit, it is being fed by feeder conductors, supplying a branch circuit breaker panel.

Do not confuse the terms grounding and bonding. If these feeders originate at a main panel in another structure, they must be accompanied by a properly sized equipment grounding conductor. This EGC must be terminated in a auxiliary grounding bus in the new breaker panel, and it must be kept isolated from the neutral conductors (do not install the main bonding jumper screw in the neutral bus). The grounding electrode conductor should also terminate at the auxiliary ground bus. This auxiliary grounding bus is most often a separately purchased option.

[Abe Music]

Hey all, my apologies for not being active on the thread I started...apparently I had my notification settings relaxed or something. At any rate, I thank all of you for your input.

Some updates:

I've noticed some discussion around ground rods and such and I've already got the ground rods on the detached building. Next weekend we're going to try to disconnect the existing cable and see if it can be pulled through...if so, then it should certainly remove any major complexities in the job.

Also, I had a second quote come in at over $2000 and that was for pulling #6 (IIRC) for 60 amp service and installing a surface mount box :eek: That just seems soooo expensive. I'm visiting my wife's family right now and her uncle is a contractor with appropriate licenses for a different state, but he said this is not a job he would personally pay that much for. He's offered to come down in a couple months and help me do the job if I supply the materials. I'll need to check with local codes to see if this is something I can do as a home owner or if I'll need an inspection before/after.

An additional update that's interesting and I may end up going for is I spoke to the electric company about adding a 200amp service to the detached garage. I would be required to trench, supply 3" schedule 40 along with an appropriate pull rope, and the disconnect. They would supply the cable and labor to pull it and attach it up. I could then add my panel inside and basically be future proof for anything I'd like to do in there (like maybe adding a small heat pump for when I finish out the attic and move my home office there.)

[Abe Music]

It's in Mount Juliet, but your idea is something I'm certainly considering. I will need to check on the local codes for this, but at my last house I was able to do my own work without issue.