Go Back  DoItYourself.com Community Forums > Electrical, AC & DC. Electronic Equipment and Computers > Electrical - AC & DC
Reload this Page >

Ballpark Gue$$timate - Adding a Subpanel to a Detached Garage...

Ballpark Gue$$timate - Adding a Subpanel to a Detached Garage...


  #1  
Old 11-06-14, 07:53 AM
B
Member
Thread Starter
Join Date: Dec 2008
Location: Central MA
Posts: 215
Upvotes: 0
Received 0 Upvotes on 0 Posts
Ballpark Gue$$timate - Adding a Subpanel to a Detached Garage...

So I want to add electricity to my garage. My town does not allow me to do my own electrical work no matter what, even if I pull a permit and have it properly inspected. I can't even change a light switch without a permit. A licensed electrician must fill out the form or it will be rejected..... Oddly enough the electrical inspector is also the inspector for the neighboring town which will allow you to do your own work. I guess its an old town by-law from the knob-and-tube days. Okay...I'm done ranting.

Anywho.....it looks like I am going to have to pay somebody. I have a detached garage about 20' from my house. There is about 40' from that side of the house to the existing 200A electrical panel.

What would be a guesstimate for an electrician to run lets say 75' of wire and add a 50A subpanel?

I'd dig the trench and run the conduit. Any guesses?
 
  #2  
Old 11-06-14, 10:08 AM
Z
Forum Topic Moderator
Join Date: Sep 2005
Location: USA
Posts: 6,099
Received 422 Upvotes on 375 Posts
I really have issues with locales that don't allow homeowners to do their own permitted work. I think it just results in a lot of homeowners doing shoddy work without permits. But I'll hold back on my ranting too...

The best way to find out is to call an electrician or two. Talk to them about what you can do and what they'll do.

If I had to guess though, $800-$2,000. I'm not a pro, so I don't really have much basis for that estimate - but a lot will depend on what happens once you hit the panel in your garage. Do you want lights, receptacles, etc? Pulling wire through conduit is easy, but what happens once it hits inside your house? Transition to NM-B? Same in the garage, though it needs to be protected.
 
  #3  
Old 11-06-14, 10:53 AM
B
Member
Thread Starter
Join Date: Dec 2008
Location: Central MA
Posts: 215
Upvotes: 0
Received 0 Upvotes on 0 Posts
I was expecting to run about 45' of 6/3 NM-B from the existing 200A panel to the junction box where the conduit will start. Then about 25-30' of 6AWG THHN through the conduit to the new 50A sub-panel.

Just browsing the online stores if I add up the wire, sub-panel, ground rod, ground bar, breakers, conduit etc....it comes to about $400 in parts. So knowing what I would pay at the big box store, I'm wondering what an electrician would tack on as labor to run the wire and install the panel.

I'm not looking for any wiring in the garage. Maybe just a single 20A outlet connected to the panel. The rest of the wiring will be added in "future renovations and upgrades".

Last thought....does NM-B need to be protected in a detached garage? I always thought it was okay for it to run through studs/rafters in a garage since it wasn't a living space. Much like it can run overhead along a floor joist in a basement.

Thanks!
 
  #4  
Old 11-06-14, 11:02 AM
I
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 9,785
Upvotes: 0
Received 45 Upvotes on 43 Posts
The plan sounds pretty solid to me. You didn't mention it yet but ground rods will be required at the garage. Rough guess would be in the $1k area assuming you do or subcontract the trench and the other areas are accessbile, but local rates, permits and taxes vary a lot which could change the total.

NM should be OK through the rafters in a garage area, but may need a 2x4 running board if the garage has an attic. It probably should be protected if it runs through the walls below 8'. The actual height is subjective up to your inspector as to where damage is likely.

What are you actually going to run on the subpanel? Is the 50A just a guess or do you have specific future use in mind?
 
  #5  
Old 11-06-14, 11:23 AM
B
Member
Thread Starter
Join Date: Dec 2008
Location: Central MA
Posts: 215
Upvotes: 0
Received 0 Upvotes on 0 Posts
Again...thanks for the replies! I'm aware of the ground rod in the garage as well as installing a separate ground bar in the panel.

The garage will be my workshop for all things automotive and woodworking related. Its a small structure at 20x20 and has a low slope roof....so no attic. Aside from running lights and a radio it may have up to two machines running at the same time. i.e. a dust collector and a table saw. Maybe a 240V outlet to connect a welder to someday.

50A seems fine for me. There is only so much I can do at a single time in the small space.

It really is a shame I can't do my own work. My town is a regular old blue collar town and there are a lot of thick headed people. I'm sure this by-law was well intended to stop people from doing faulty work....but I'd be willing to guess it only increased the amount of work that was being done without being inspected.

If it gets inspected....and passes, who cares if a professional or a homeowner does the work. Ugh...getting my blood pressure up!
 
  #6  
Old 11-06-14, 11:27 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 13,979
Received 194 Upvotes on 170 Posts
Depending on the code cycle you are under the nm in the shed would require a 15 minute finish to be installed.
 
  #7  
Old 11-06-14, 11:38 AM
B
Member
Thread Starter
Join Date: Dec 2008
Location: Central MA
Posts: 215
Upvotes: 0
Received 0 Upvotes on 0 Posts
15-minute finish.....Had to look that one up! I hope my town doesn't require it. Its a 115 year old garage with rough cut studs that are unequally spaced and unequally dimensioned. Drywall does not belong in that structure.

If it came down to it I'd run conduit. Being so small it wouldn't be a big deal.
 
  #8  
Old 11-06-14, 01:17 PM
F
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 16,321
Received 38 Upvotes on 30 Posts
PC, is the 15 minute cover a new NEC requirement or a local code issue?


From what I have gathered over the years Taxachusetts is one of the most UNfriendly to DIY as well as one of the most regulated states around. I remember an episode of This Old House where Rich Trethewey was installing some PVC drain piping and Bob Vila remarked that it was so easy that any home owner could do it. Trethewey immediately protested, stating that one HAD to have a license to do it. It is BS like this that is often the cause of uninspected work and results in fires or worse. REASONABLE requirements I am all for but this is not reasonable.


I remember for years plastic piping was not allowed in Seattle for any purpose. Not so coincidentally one of the (very) long term city councilmen was also a member of the family that owned the largest plumbing company in the county. Amazingly, shortly after this councilman was defeated in an election, plastic piping was soon approved. I don't know for a fact, but I heard the same was true with copper piping many years earlier while this same councilman was in office.
 
  #9  
Old 11-06-14, 02:01 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 13,979
Received 194 Upvotes on 170 Posts
The finish is actually a NEC requirement for NM in outbuildings. It has been dropped in later editions. It did not really make sense since the same cable could be run with no finish in the house.
 
  #10  
Old 11-07-14, 04:52 AM
B
Member
Thread Starter
Join Date: Dec 2008
Location: Central MA
Posts: 215
Upvotes: 0
Received 0 Upvotes on 0 Posts
MA is most definitely an unfriendly place for DIY'ers. Most everything requires special licenses or a licensed professional has to do it.

Well guess what..the state is probably littered with work done by incompetent people that was never inspected. Because they didn't want to spend $150 for someone to change an outlet or a hose spigot.

Thanks for the help guys. But I will add one last question before I'm done.

For the electricians out there.....how would you feel if you came to give an estimate and found that prior to you showing up, the homeowner (me) ran the NM-B 6/3, installed the conduit, and pulled the wire.

All you would need to do would be to connect the NM to the main panel, splice the NM to the THHN in the junction box, and wire up the sub panel????

Would you be pissed and not want to touch it? Or would you quote it accordingly? Of would you increase the $$$ because someone (me) did work that you could have been paid for?

Thanks!
 
  #11  
Old 11-07-14, 05:33 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 13,979
Received 194 Upvotes on 170 Posts
Depending on what I saw the price may go up since I now have to check all your work vs knowing the quality of mine. There times when the homeowners uses the wrong material and it all needs to come out. Also the contractor is now assured responsibility for your work. Some will not touch it.
 
  #12  
Old 11-07-14, 05:43 AM
B
Member
Thread Starter
Join Date: Dec 2008
Location: Central MA
Posts: 215
Upvotes: 0
Received 0 Upvotes on 0 Posts
Good to know....thank you. I'll just run the PVC from the house to the garage and be done with it. No need to complicate things for the electrician.

I suppose unless I have a good relationship with an electrician and he knows/trusts my work....its probably just not worth it to "help".

Still PO'd that I can't do this myself though. Even if I put in writing all the things I plan to do...and all the codes I plan to adhere to...nuthin. 1st line on the permit is your license #.
 
  #13  
Old 11-07-14, 06:38 AM
A
Member
Join Date: Sep 2009
Location: USA
Posts: 477
Received 5 Upvotes on 4 Posts
For the electricians out there.....how would you feel if you came to give an estimate and found that prior to you showing up, the homeowner (me) ran the NM-B 6/3, installed the conduit, and pulled the wire.
I know my boss wouldn't mind. He'd charge you extra to pull out the incorrect wire, NM can't be run in a wet location.
 
  #14  
Old 11-07-14, 06:41 AM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 9,872
Received 185 Upvotes on 166 Posts
how would you feel if you came to give an estimate and found that prior to you showing up, the homeowner (me) ran the NM-B 6/3, installed the conduit, and pulled the wire.
It's not a question of how someone would feel, but more of a question of will it pass inspection? The answer is no. Pulling out and replacing the NM-B cable would be included in the estimate. The proposal would also have qualifications added in case the inspector wanted to see the depth of the conduit which means, any additional work required for the conduit to be approved by the inspector would be at additional cost to the customer based upon T&M rates.
 
  #15  
Old 11-07-14, 06:47 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 13,979
Received 194 Upvotes on 170 Posts
The NM was going to run to a junction box where it would transition to THWN when going into the conduit, not NM outside in conduit.
 
  #16  
Old 11-07-14, 06:53 AM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 9,872
Received 185 Upvotes on 166 Posts
The NM was going to run to a junction box where it would transition to THWN when going into the conduit, not NM outside in conduit.
But the issue of the underground conduit installation not being inspected is still there.
 
  #17  
Old 11-07-14, 07:46 AM
B
Member
Thread Starter
Join Date: Dec 2008
Location: Central MA
Posts: 215
Upvotes: 0
Received 0 Upvotes on 0 Posts
Right. If I were to dig the trench for the conduit, and then run the conduit.....I would leave it at that. I would leave the trench open for the electrician/inspector to measure depths, etc.

The electrician would show up with PVC in place and all he would have to do is pull the wire. I'll take care of the dirty work and let the pro's take it from there. The electrician can notify the inspector when inspections are needed....since the electrician is going to be the one pulling the permit.
 
  #18  
Old 11-07-14, 07:50 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 13,979
Received 194 Upvotes on 170 Posts
I just throw a few shovels of dirt to hold it down while waiting for the inspection.
 
  #19  
Old 11-07-14, 08:58 AM
I
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 9,785
Upvotes: 0
Received 45 Upvotes on 43 Posts
I would generally be OK with it, but a heads-up in advance would be nice just to make sure you've got the right material, right location and some details like depth and cable protection requirement. I would subcontract the trenching in any case, so one less thing to deal with if you did it correctly. Sometimes local areas have goofy rules that only your contractor will know -- best to be aware of those gotchas before you do a bunch of work.
 
  #20  
Old 11-07-14, 11:28 AM
Mr.Awesome's Avatar
Member
Join Date: Oct 2013
Location: Canada
Posts: 511
Received 0 Upvotes on 0 Posts
You could always ask your electrician what you could to do help him and your wallet out.
I had a friend's dad ask me that when I wired his garage. He ended up drilling all my holes in studs and cut out holes for exterior lights and receptacles for me. Made the job a cakewalk and there were zero complaints from me on making my job easier.
And as far as inspecting your work would go...
You could do the whole job yourself and it wouldn't take long at all to inspect the panels and conduit. The trouble is if you do something wrong, then you're paying double for the electrician to disassemble your work and re do it.
 
  #21  
Old 11-21-14, 05:35 AM
B
Member
Thread Starter
Join Date: Dec 2008
Location: Central MA
Posts: 215
Upvotes: 0
Received 0 Upvotes on 0 Posts
Okay...back from the dead!!!! I've been putting a roof on this garage lately so I've spent a bunch of time thinking about options....

What about installing another electric meter? There is a clear shot between the street and the garage. Its probably a 75' run. The only hitch is that the new wires would cross my neighbors driveway so I'm sure there would have to be some minimum height that would have to be met.

Is this a common practice? My garage has a low sloped roof and is about 7-8' high at the back end and about 9-10' at the front. I'm sure a galvanized pipe would have to stick above the roof to make sure that the minimum height is met over me neighbors driveway.

Lastly...when the electrical company installs new service.....how does that work.....does the electrical company pay for the wire and labor up to the box? Or do they send me a bill?

Thanks!
 
  #22  
Old 11-21-14, 05:55 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 13,979
Received 194 Upvotes on 170 Posts
A second service to the same property is seldom allowed. If it is the second meter get charged a commercial rate which is higher than residential.

If it were allowed you would need to meet the clearances over driveways.
 
  #23  
Old 11-21-14, 07:56 AM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 9,872
Received 185 Upvotes on 166 Posts
The only hitch is that the new wires would cross my neighbors driveway so I'm sure there would have to be some minimum height that would have to be met.
Yes, there is a minimum height the drop would have to meet, but it's not likely the power company would do this. Although common at one time, most power companies will not run across a neighbor's property any more. A service drop doesn't have to come from the power pole, but can also come from the span between two poles (called a flying dutchman). It's pretty rare to find two meters on a residential property.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: