Wiring garage myself?

[locomike]

I am thinking about having the service wire ran and the subpanel installed and then wiring the garage myself. Would I be saving very much money by doing this part myself? I am fairly confident I can handle the task. I'll just have to double check and make sure I get it all "to code".
I'm probably gonna be going with a 30x40x10 or maybe smaller depending on cost. I plan on having 100 amp service. Probably go with a bunch of 8' flourescent lights on 2 individual 15 amp circuits, have a couple cirucuits with 15amp receptacles, and then ofcourse a 220v outlet. I have a 220v extension cord so I will debate on whether putting more than 1 220v receptacle. It will probably be a pole barn so I will have to see what is allowed for wiring although I don't think there is much regulation out in the country where I live. On a scale of 1 to 10 really how hard is it to do this yourself.

 

[locomike]

Yeah in my shop in town I wired up my outlet for my welder and I used a NEMA 6-50R. First time I had ever messed with ANY electric but I did my homework until I was confident and now I love messing with electrical. I even learned a good bit about 3phase since that is what is in my shop. Not bad for not knowing anything previously. I just love learning new things and reading and then doing it. Yeah I figure once they get it built I can go in and take my time and have something to be proud of lol. Figure it will be kool to say "yeah, I did all the wiring myself". It is probably gonna be a polebarn so I might end up going with EMT which is fine because my shop is block and has EMT ran all throughout. Saving money is always a plus too. Thanks for your feedback. Mike

 

[Charles (in GA)]

A better suggestion than the mini code book is the whole National Electrical Code 2008 by the National Fire Protection Association (NFPA) and Illustrated Guide to the National Electric Code by Charles R. Miller.

The Illustrated guide is worth its weight in "gold" and it has references to the code book so you can go and look up the actual code section that pertains to the subject it is showing you. I am quite impressed with it.

The money you spend (about $125) is well worth it.

Charles

 

[logical]

It isn't really hard at all but you need to keep it simple and only do what you are sure you know is correct. I did my basement and parts of my garage.

I can only suggest you rethink those 15 amp circuits for outlets. If you want to run a miter saw and a vacuum to collect the saw dust together you'll likely blow a 15 amp. The 12 gauge wire and slightly more expensive components will cost a bit more but you'll be glad you did it. If you do use some 15 where you know you'll just be using a radio or cordless tool chargers, etc, consider using a different color recepticle. I did all 20 amps but I've seen some use white for 15 amp and grey for 20.

 

[Torque1st]

While you are at it and saving big bucks with DIY install a 30A outlet for the compressor if that will run it, a 50A for the welder, two or three 15A lighting circuits, and 4 ea 20A circuits for multiple outlets for each wall, a 20A for the shop refer, another 20A for the shop microwave, 20A for the coffee pot and TV/Stereo, 15A for the overhead drop cord, 20A for the unit heater, and an extra 20A for the power tool bench. When you run the lighting circuits install some outlets up high for those 4' shop lights you can hang from chain any place you need some extra light. Don't forget the motion detector light outside and inside... Then get some insulation up before you clutter the walls too bad.

 

[Printer Mike]

A little lube makes pulling wires a lot easier!

 

[sajohnson]

Go for it.

The above advice is all very good.

I would only add that it never hurts to up-size wire -- especially for long runs and/or heavy loads. The NEC is primarily concerned with safety (i.e. breakers sized to protect the wiring from getting too hot) but there are code compliant situations where a lot of voltage (and power) is dropped across the wiring.

For example, the wiring where I work is all very well done, but we've seen the line voltage drop from 118-120 v down to about 105 v when running a small microwave (~600W) and a small coffee maker (also about 600W).

It's kind of like running a bit larger fuel line and fuel filter than the engine requires -- it doesn't hurt anything and eliminates that as a weak link.

 

[logical]

All good advice. Certainly use 20A breaker and 12 guage wire for the general service outlets. You will likely need a GFCI outlet at the start of each run. You can still use the 15A outlets though, with multiple of them on the 20A circuit.

..............

What? Are you suggesting he use a 20A breaker and then outlet recepticals only rated at 15A????????? That may be technically allowed but why would you do that?

 

[timgr]

The Illustrated guide is worth its weight in "gold" and it has references to the code book so you can go and look up the actual code section that pertains to the subject it is showing you. I am quite impressed with it.
...

Charles, how important is it that I get the 4th (most current edition) of this "illustrated guide" book? I looked on Alibris and found a 2002 (2nd ed.) for substantially less.

The Amazon used books will save you money too - note that the book price reduction has to be less than the cost of shipping to make it worthwhile.

 

[Charles (in GA)]

The fourth edition is directly related to the new 2008 code (it has a publish date of late 2007) while the earlier books are, related to their respective earlier versions of the code.

Somewhere along the line, much of the code was re-numbered, don't recall which year, I kinda think '99 was the old numbering while '02 was the first of the new numbering (code is revised and reissued every three years). There are quite a few changes being made to the code each time, so I cannot see that the older version would be of much use, unless you live in a county/city that specifies an older version of the code as their standard (and many locales do). In that case, you want the matching version of the code.

Charles

 

[Printer Mike]

I just thought of something else that might help. Be generous with the length of wire in the receptacle boxes. It's so much better to cut off excess that to wish the wires were a little longer. I learned this the hard way...

 

[logical]

Yes. With multiple of them on a 20A breaker with 12 guage, it is fine. Done all the time.

If he has any tools that actually need 20A they will have a 20A plug, and not be able to fit in the 15A receptacle. These are rare, though.

Any one tool with a 15A plug should never exceed 15A. To have many of them on a 20A breaker with the proper wire for the breaker (12 guage) is fine. Multilple loads at the same time can add up to 20A before tripping the breaker.

If you put ANY 20A receptacles (the ones with one blade going the other way) on a circuit then the breaker MUST be 20A.

The 15A commercial grade recepticles are $1.98, the 20A versions are $2.15. I'm just saying I did and would reccomend the 20's. For under $2 per garage, I am not limited to where I can plug something in.

 

[kvom]

I am in the process of wiring my new garage/shop. I have a friend who is an electrician who is helping/directing. While I do need to pay him, the amount of time I am saving is well worth it, and I'm not risking making any mistakes. Where I am the code inspections are pretty strict. That said, there is nothing particularly difficult (other than trying to staple 10ga wire to overhead joists standing on a ladder).

We are required to use 12ga wire for all 110v outlets in the shop.

 

[Matti]

I bought a condensed code book and did a few basements over ht last 15 years. A garage can be a bigger job with the panel and service wiring. Having somebody to consult with (other than Home Depot guy ) can be a big help. Otherwise it is pretty straightforward.

 

[Stuart in MN]

What? Are you suggesting he use a 20A breaker and then outlet recepticals only rated at 15A????????? That may be technically allowed but why would you do that?

All 15 amp receptacles are rated for 20 amps 'feed through'. The NEC (in article 210.21) specifically allows their use on 20 amp circuits, as long as there is more than one receptacle (and a regular duplex receptacle counts as two, you can get them with a single receptacle but they aren't very common.)

By the way, you can look at the National Electric Code online, at the NFPA website: http://www.nfpa.org/aboutthecodes/AboutTheCodes.asp?DocNum=70 . The 2002, 2005 and 2008 versions are available since not all parts of the country are using the latest version yet. You can't print it out, but it is handy for looking up things. Also, remember that the NEC is not a design book or instruction manual, it's a list of the minimum requirements considered necessary for safety.

 

[ovilla]

I'd also talk to your local buidling inspector office to find out what is code for your town. I have a friiend who wired up his basement just fine (with the correct wire size for all outlets and circuits), only to later find out that in his town they mandate the use of conduit. He had used Romex everywhere.

 

[ddawg16]

I just thought of something else that might help. Be generous with the length of wire in the receptacle boxes. It's so much better to cut off excess that to wish the wires were a little longer. I learned this the hard way...

Agree....or take it a step further....what I do (especially in older homes) is use a pig tail....you don't want to use the outlet as the 'junction' box, i.e., connect the incomming to one set of terminals and then connect the feed to the next box on the other set of terminals. Instead, wire nut the wires together in the box with a pig tail....you then connect this single wire to the outlet. That way, all of the available 20A is flowing directly down the Romex...your outlet will only use what the load is on it....

And more importantly...it's a lot easier to move that duplex socket around with only three 3 on it instead of 6....AND..you are only bending the pig tail wires...hence, less chance of the main feed wires breaking.

And yes on seperate feed for the lights....The lights in my house and garage have their own breakers...when I redo the garage I'm going to have two sets of feeds....better to loose half than all....as correctly pointed out...you don't want it to go dark while the blade is still turning...you at least want to watch the carnage as it happens.....

 

[pmiranda]

Agree....or take it a step further....what I do (especially in older homes) is use a pig tail....you don't want to use the outlet as the 'junction' box, i.e., connect the incomming to one set of terminals and then connect the feed to the next box on the other set of terminals. Instead, wire nut the wires together in the box with a pig tail....you then connect this single wire to the outlet. That way, all of the available 20A is flowing directly down the Romex...your outlet will only use what the load is on it....

Seems like you're adding another point of failure there. If you do this, you'll want to use the deeper boxes... even if the NEC fill requirements don't call for it (I think they might, but depends on a few factors), you'll need a little extra space to make it easy to stuff in there.

I also wouldn't do this for the first outlet in a series since you want to cover everything downstream with GFI.

Interesting tip, though!

 

[logical]

Agree....or take it a step further....what I do (especially in older homes) is use a pig tail....you don't want to use the outlet as the 'junction' box, i.e., connect the incomming to one set of terminals and then connect the feed to the next box on the other set of terminals. Instead, wire nut the wires together in the box with a pig tail....you then connect this single wire to the outlet. That way, all of the available 20A is flowing directly down the Romex...your outlet will only use what the load is on it....

And more importantly...it's a lot easier to move that duplex socket around with only three 3 on it instead of 6....AND..you are only bending the pig tail wires...hence, less chance of the main feed wires breaking.

And yes on seperate feed for the lights....The lights in my house and garage have their own breakers...when I redo the garage I'm going to have two sets of feeds....better to loose half than all....as correctly pointed out...you don't want it to go dark while the blade is still turning...you at least want to watch the carnage as it happens.....

Aperage doesn't flow like water. Regardless of which method you use there are 110 volts between the wires at any point along the circuit. Pluging somthing in along the way doesn't effect the downstream wires any more or less by using the pigtails. All that does replace one set of recepticle terminations with a set of wire nut connections.

 

[Charles (in GA)]

Having somebody to consult with (other than Home Depot guy ) can be a big help. Otherwise it is pretty straightforward.

Sometimes the Home Depot guy can be more help than you realize. When I was replacing the panel in my parents house (and the meter socket, disconnect, service entrance cables from the weather head all the way in to the panel, etc) I found the Home Depot guy very well versed in the code. Turns out he was a retired electrician, and enjoyed working there helping others and meeting old cronies still working in the field. When I called for a building inspector to come and look it over, the inspector was impressed with the neatness, then I told him "there's this old guy at Home Depot in the electrical department. He set me straight on alot of things, lots of good advise" and then inspector then brightened up.... "thats my DAD!" he told me.

After talking to him, he realized I was coming from out of town to work on this project and the house was unoccupied, so he called on the radio and told the inspection office to get the power company out there right then to do the hook up while I was still there, to save me the hassles of making another trip just to meet the power company.

Charles

 

[Matti]

I am thinking about having the service wire ran and the subpanel installed and then wiring the garage myself. Would I be saving very much money by doing this part myself? I am fairly confident I can handle the task. I'll just have to double check and make sure I get it all "to code".
I'm probably gonna be going with a 30x40x10 or maybe smaller depending on cost. I plan on having 100 amp service. Probably go with a bunch of 8' flourescent lights on 2 individual 15 amp circuits, have a couple cirucuits with 15amp receptacles, and then ofcourse a 220v outlet. I have a 220v extension cord so I will debate on whether putting more than 1 220v receptacle. It will probably be a pole barn so I will have to see what is allowed for wiring although I don't think there is much regulation out in the country where I live. On a scale of 1 to 10 really how hard is it to do this yourself.

I'm just finishing the wiring for my new 24x26 garage. You will save lots of labor costs for sure. However, I'm finding material costs are staggering. I think I've spent $2000 so far which includes a 125 A panel, breakers, meter box. 2 masts (overhead service to garage), #2 underground aluminum cable (underground to house), #3 copper primary cable, 500 feet of 14/2, 60 feet of 8/3, 65 feet of 12/2, boxes, conduit, connectors, etc. I haven't bought lights yet which is another $600.

 

[BigChevy80]

Agree....or take it a step further....what I do (especially in older homes) is use a pig tail....you don't want to use the outlet as the 'junction' box, i.e., connect the incomming to one set of terminals and then connect the feed to the next box on the other set of terminals. Instead, wire nut the wires together in the box with a pig tail....you then connect this single wire to the outlet. That way, all of the available 20A is flowing directly down the Romex...your outlet will only use what the load is on it....

No point in doing this... other than making more work for yourself and creating more failure points in the circuit. Each receptacle is rated for 20 amps so there's no point in worrying about how much current is flowing through them. If you pull more than 20 amps you're going to trip the breaker anyway.

 

[larry4406]

Regarding the 15A versus 20A receptacles, I think if you read the packaging carefully, the "stab" conncts are 15A while the screw terminals are 20A (at least mine are). The $ for the 20A receptacles with the "sideways" prong is about useless to me as I don't have any power tools with that type of plug. Do yourself a favor - don't use the stabs. Take your time and use the screw terminals.

 

[Todd.Brock]

I agree with Kvom. I just finished wiring my basement with a little help. A guy from church is a licensed electrician and came over and gave me some pointers to get started. I have run new circuits before but a sub panel was new to me. A construction buddy gave me a length of 2-2-2 4 service wire to run the sub panel, 100 amp sub is overkill for what we did but it was free. I ran all the wire and anywhere I had questions, I left it alone. The electrician came back and inspected all my work, pointed out problem areas and corrected. Im handy and not scared to tackle many things, but I wasnt burnin down the house.... Bug your electrical buddy and ask questions until your comfortable, dont assume/hope you did it correctly. Just my 2cents. The code book is a great resource, I spent quite a few nights reading electrical books before I really got started.

 

[Bib Overalls]

I have a metal framed building (Adam's Truss) with 2x4s run horizontally at 2 foot intervals. I ran all of my circuit cables out of a the service box through a 2" plastic conduit that terminates at the 8 foot high horizontal. The cables for my outlets are stapled to the top of this horizontal and run behind the building's vertical posts. At outlet locations the cable runs into a handy box. From this handy box I ran a 1/2 inch metal conduit to a second handy box at the 4 foot high horizontal. I made a three way splice in all of the wires in the upper box and ran the legs down to 20 amp rated (gray) outlets in the lower box. This protects the wires according to code. You can see one of my outlets in the right side of the attached picture.

I have a 30' 40' shop and used three outlet circuits and two lighting circuits. I also installed a 50 amp 220 welder outlet at the service box and a 30 amp 220 outlet for the compressor.

 

[tdkkart]

No point in doing this... other than making more work for yourself and creating more failure points in the circuit. Each receptacle is rated for 20 amps so there's no point in worrying about how much current is flowing through them. If you pull more than 20 amps you're going to trip the breaker anyway.

While I agree with the logic behind your statement, especially the more points of failure part, unfortunately pigtails are code in alot of places.
All the pigtails do is make for MORE stuff to cram in an already too small box(even when following the box fill guidelines), and extra potential safety issues.


Wirenuts, screw terminals, screw clamps, crimps etc that are used everywhere in residential and industrial wiring applications are all points of possible failure. If you're lucky these connections will only loosen and lose contact shutting off your power. If you're unlucky they will loosen and cause a high resistance point, which then overheats, starts a fire and burns your building down.

There are places where you have no choice but to use screw terminals and clamps, but IMO they should be kept to a minimum.

Soldering is the only proper way to connect two pieces of wire, and will never come loose if done correctly. Unfortunately damn few people can solder correctly so wire nuts are easier and "safer" according to the codes.

 

[kbs2244]

I use the pig tail idea all the time.
It is a lot easier to sit at a bench and wire up the box face then to stand at each location and do it.
And the cost of "deep" boxs is worth it!
As is 3/4 instead of 1/2 pipe.

 

[sajohnson]

Regarding the 15A versus 20A receptacles, I think if you read the packaging carefully, the "stab" conncts are 15A while the screw terminals are 20A (at least mine are). The $ for the 20A receptacles with the "sideways" prong is about useless to me as I don't have any power tools with that type of plug. Do yourself a favor - don't use the stabs. Take your time and use the screw terminals.

I've always used the screw terminals. Recently however I was replacing some damaged outlets in a building that was built and wired over 30 years ago. I found that the wire was somewhat brittle and a couple of them were very short. I didn't want to risk breaking the wires so I used the stabs.

Also, I switched a couple of the outlets to GFIs. Since they're wider than a standard outlet the fit in the old narrow metal boxes was pretty tight and I didn't want to risk a short to the box. There again using the stabs made sense.

Since it was the first time I'd used them I looked at them very closely and they seem to be very well constructed -- good grip and lots of contact area. Offhand, I don't see why they would be rated lower than the screw terminals. Any idea?

I agree about the 20A outlets. I can't remember the last time I saw a device with the special 20A plug. Maybe on a high output 120V window A/C unit?

I wired my garage with two 20A outlet circuits, each protected with a GFI outlet feeding standard outlets. I figure that if I ever need a 20A outlet I'll but one and put it in.

The only exceptions were a 30A 240V outlet for the compressor (2 stage Quincy monster!) and another 30A 240V twistlock outlet that is a spare and could be used to backfeed the panel with the generator.

 

[wilbilt]

I would not skimp on the receptacles. It is annoying when cords won't stay plugged in after a couple of years when using cheap $2 receptacles.

I would spend a few bucks more and use quality spec-grade parts.

 

[sajohnson]

While I agree with the logic behind your statement, especially the more points of failure part, unfortunately pigtails are code in alot of places.
All the pigtails do is make for MORE stuff to cram in an already too small box(even when following the box fill guidelines), and extra potential safety issues.


Wirenuts, screw terminals, screw clamps, crimps etc that are used everywhere in residential and industrial wiring applications are all points of possible failure. If you're lucky these connections will only loosen and lose contact shutting off your power. If you're unlucky they will loosen and cause a high resistance point, which then overheats, starts a fire and burns your building down.

There are places where you have no choice but to use screw terminals and clamps, but IMO they should be kept to a minimum.

Soldering is the only proper way to connect two pieces of wire, and will never come loose if done correctly. Unfortunately damn few people can solder correctly so wire nuts are easier and "safer" according to the codes.

I have an electronics background, so I'm very familiar with soldering and agree that it is the next best thing to a solid wire.

Actually, in working on the building I mentioned in my post above, I came across some bare ground wires in a box that had been soldered -- everything else was typical (wire nuts, screw terminals).

I was talking with a coworker about the soldered connections I found and he suggested that while soldering is good for low current electronic connections, any connection that might potentially get hot should have some sort of mechanical connection or be exothermically welded. The idea is that if the wiring gets too hot, the solder might melt.

Maybe the best (but time-consuming) would be to twist the wires together, solder them, and then install a wire nut?

With connections in metal boxes I feel safe with wires twisted tightly together and capped with a wire nut and maybe some electrical tape.

Anyone know what the NEC says about this?

 

[sajohnson]

I use the pig tail idea all the time.
It is a lot easier to sit at a bench and wire up the box face then to stand at each location and do it.
And the cost of "deep" boxs is worth it!
As is 3/4 instead of 1/2 pipe.

Good point!

 

[sajohnson]

I would not skimp on the receptacles. It is annoying when cords won't stay plugged in after a couple of years when using cheap $2 receptacles.

I would spend a few bucks more and use quality spec-grade parts.

Very true.

It might make sense to at least use the spec grade receptacles in 'high use' areas like the work bench. Maybe others along the walls that will only get occasional use could be standard grade.

 

[tdkkart]

The idea is that if the wiring gets too hot, the solder might melt.

Which would be a good thing IMO, I'd much rather have a bad circuit melt the solder and disconnect itself than continue malfunctioning.

Properly fused or breakered, I doubt that any circuit would get hot enough to melt solder before shutting down.

 

[sajohnson]

Which would be a good thing IMO, I'd much rather have a bad circuit melt the solder and disconnect itself than continue malfunctioning.

Properly fused or breakered, I doubt that any circuit would get hot enough to melt solder before shutting down.

True.

I think the mechanical/exothermic recommendation (NEC requirement?) is primarily for grounds, which might get fried by a lightning strike. The concern is that a soldered connection could open up or become resistive and there would be no sign of it. The circuit/load would continue to operate normally but would no longer be grounded.

That's my understanding anyway. Can anyone shed some light on this?

I don't have time now, but later I'll check the NEC online and see if I can find anything.

For anyone who's interested, this was posted by someone else:

"By the way, you can look at the National Electric Code online, at the NFPA website: http://www.nfpa.org/aboutthecodes/Ab....asp?DocNum=70 . The 2002, 2005 and 2008 versions are available since not all parts of the country are using the latest version yet. You can't print it out, but it is handy for looking up things. Also, remember that the NEC is not a design book or instruction manual, it's a list of the minimum requirements considered necessary for safety."

If that link doesn't work, try this one:
http://www.nfpa.org/aboutthecodes/AboutTheCodes.asp?DocNum=70&cookie_test=1

Once there, click on the link under, "Additional info about this document".

 

[locomike]

Lots of great info. Thx for all the info guys. Hope it helps others.

 

[Charles (in GA)]

With all the discussion about pigtails to outlets vs using outlet screw terminals to make the connection, please note that NEC 300.13B requires in Multi-wire circuits (those with two hots from opposing phases or poles and sharing a neutral/grounded conductor) that the neutral be connected in such a manner that the continuity of the neutral "shall not depend on device connections such as lampholders, receptacles, and so forth, where the removal of such devices would interrupt the continuity".

In other words, the neutral in multi-wire circuits must be pigtailed.

About the discussion on soldering as a method of splicing wires, NEC 110.14 tells us that when soldering, the wires must first be "mechanically and electrically secure without solder and then soldered" and then "covered with an insulation equivalent to that of the conductors or with a insulation device identified for the purpose". Thus the electrical tape used to wrap the wires must be at least the same temp rating as the wire insulation is.

Charles

 

[locomike]

LOTS of useful info. Need to get me a code book.

 

[ddawg16]

Truth is.....wire nuts do a pretty damned good job.....I have never seen an issue where they were used.....except when a size too small was used.

When you look at what happens when you splice two or three wires togther with wire nuts....you see that the wires get twisted together creating a lot of surface contact....

While I tend to solder a lot of the connections that I use on my jeep....I would hesitate to solder wires in my house......two problems.....what if you want to take the connection apart? It means you either cut or de-solder. Second, because the wire is typically 14 or 12 G, it takes a lot of heat to solder those wires together....that heat tends to weaken the insulation....that could be a bigger problem than anything else.

I see no reason to re-invent the wheel....looks like it's been turning for almost 100 years....

So...when did wire nuts first get used?

 

[sajohnson]

Truth is.....wire nuts do a pretty damned good job.....I have never seen an issue where they were used.....except when a size too small was used.

When you look at what happens when you splice two or three wires togther with wire nuts....you see that the wires get twisted together creating a lot of surface contact....

While I tend to solder a lot of the connections that I use on my jeep....I would hesitate to solder wires in my house......two problems.....what if you want to take the connection apart? It means you either cut or de-solder. Second, because the wire is typically 14 or 12 G, it takes a lot of heat to solder those wires together....that heat tends to weaken the insulation....that could be a bigger problem than anything else.

I see no reason to re-invent the wheel....looks like it's been turning for almost 100 years....

So...when did wire nuts first get used?

I had a wire nut loosen up inside a metal box in my basement years ago (not installed by me BTW!). I heard the arcing and opened the box to investigate. It was pretty ugly -- black conductors and charred insulation. It looked like whoever made the connection did not twist the wires together before installing the wire nut and they just worked loose.

Still, I agree that wire nuts do a good job. As with anything they must be used properly.

I don't see any need to solder connections under ordinary conditions.

 

[sajohnson]

LOTS of useful info. Need to get me a code book.

Did you happen to try the NFPA link that I posted?

They have the NEC available free (for viewing only of course).