I am in the process of building a 2400 sq. ft. woodworking shop. This will include 3 phase power, lots of outlets, lots of light, most wiring in surface mounted conduit, etc. The plan calls for two 225 amp breaker boxes (one for single phase and one for three phase). I have a bid from a local electrical contractor to do this and I am wondering. What should I expect to pay for this admittedly out of the ordinary job? I have heard estimates of $3.50 / sq. ft. for normal house wiring but this is quite different than that. Any rules of thumb out there?
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
Skim-coating with joint compound covers texture, renews old drywall and plaster, and leaves smooth surfaces ready to paint.
Featured Video
Highlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Replies
I don't know about the rule of thumb, but it seems to me that being so wide open that the labor costs would be somewhat lower than for a house of the same square footage. Also, somewhat less trim out (decorative fixtures, ceiling fans, etc.).
The materials, though, would be of higher cost and quality. Three phase components are not made in a Home Depot quality. Also, you'll want a higher grade of outlets, but we're talking $3 vs. 89¢.
RD,
Curious why you need two boxes ? We have a single Three Phase panel (250amp I think ) at my business and it runs everything we have just fine, and believe me we use some electricity. My shot blaster has a 20 HP motor just to give you an example. You can take the single phase off the same panel.
Unless of course you only have single phase coming to the building and plan to use a phase converter to run the 3p equipment.
Bill Koustenis
Advanced Automotive Machine
Waldorf Md
Agreed with Bill.....only one box is needed. Single phase (110) is just taking juice off one phase to ground.....
Single phase (220) is going from line to line, no power connection to ground.
Three phase (220) is attaching all three wires across all three phases, normally only used for electric motors.
If you have 480 VAC three phase, plus 110 and 220, then you will need a separate box or transformers.
Here's something I just googled:
View Image
I don't know what it's for, but you can see if you want 110 power, connect A, B or C to ground. 220 single phase is A to B, B-C or A-C.
If you want three phase, you connect across A, B and C.
Edited 4/7/2007 1:27 pm by PaulWaterloo
"I don't know what it's for, but you can see if you want 110 power, connect A, B or C to ground. 220 single phase is A to B, B-C or A-C."CAUTION.First of all the standard voltages are 120, 208, and 240.If the supply is 3 phase Y connection then you will have 120 on any leg to ground. BUT YOU WON'T HAVE ANY 240. The 3 phase is 208. This is often used on for places where the only 3 phase loads are AC and there is lots of 120 loads. Some, but not all motors are rated for 208 to 240.Another system is 240 delta with one transformer centertaped for the neutral.That will give you 120 to ground on TWO of the LEGS. YOU DON'T WANT TO BE ON THE 3RD LEG. If I had such a system I would want a separate panel for 120 loads. Much safer.And there are other variants..
.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Bill-
I would say that you are correct, I'm an old Navy electrician.....so I don't know residential in/outs......just wanted to explain how 3 phase works.
Interesting about the 208, never knew that. Do motors now, and they are almost always 230/460 rated....
I'm just ramblin', don't mind me....
For some reason lost in history motors are rated at the minimum end of the excepted operating voltage . So you will see motors for 120 marked as 115, 240, at 230, etc.While at the sametime electrical devices are rated at the upper end.The code book will talk about 125 volt devices. And look at a switch or receptacle and that is what you will see marked on them.But to add to confusion people call them 110 volt circuits, which I think went out with Edision's DC distribution systems..
.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Sorry, but there is absolutely no way to give a price based upon square footage, or the number of "holes," or any other simple method. Indeed, even after providing detailed specs, one can only compare quotes with the greatest of caution.
There's a lot more to this than price alone. Electrical work typically has several different methods available for any given task; the choice is best decided on factors other than cost.
The job is going to require significant "non working" time from the Electrical Contractor. He will have to spend a fair amount of time at both City Hall, and the Power Company. He will have to prepare prints, both before and after the job. These tasks will cost him nearly the same, whether he's making a garage-size shop, or a new Pentagon.
A lot of guys, who are accustomed to doing residential work, will try to do the job using residential techniques and materials. Even where such methods may be legal, they will serve you poorly in the end. Whenever something needs to be changed, or upgraded, or added, over time ... THEN you will see the true cost of having gone price shopping.
So, what are you to do? I suggest calling a few commercial property management companies ... the sort that lease out commercial and industrial spaces ... and ask them who they use for "tenant improvements." Then, call two or three of these contractors, and ask them to make a proposal. Select the 'winner' by whose proposal seems to best suit your plans.
2400 sq ft shop
From your description, would need about $2300 in materials (Plus the lights, cost there very dependent on what is chosen), without markup.
SM conduit simplifies installation, so could probably finish a job that size in less than a week using EMT. What are labor rates in your area?, here electrical is about $200/hr.
Edited 4/8/2007 12:26 am ET by junkhound
Thanks guys. I have a plan worked out by an electrical engineer who consulted with the power company. This is in a commercial zone although I don't plan to do work for the public. Therefore, it must comply with all the commercial specs. I am not skilled with electrical work so I will leave the details to the experts. I will definately get several bids. Just thought someone out there had recently completed something in this ballpark. My guess is that with the lighting (I will need a lot of that too) all materials and commercial grade everything, I will be looking in the $15 to $20,000 range.
I'm guessing at least $15,000 in wiring costs. All that conduit and heavy power is going to cost you dearly, far more than wiring a house. You need an electrician who knows what to do--some guys are average romex pullers for residential wiring, and aren't really who you want for your shop.
Bottom line, who cares?! You're going to have a huge new woodworking shop, and that's what matters.
This thread bring up one issue that, I believe, is a classic example of sheer idiocy being taught by folks without a clue. The issue : Getting multiple bids. As I've seen it presented, time and again, folks are encouraged to call everyone in the phone book for a quote, then the "smart consumer" picks the cheapest. Some "management" types even carry this farther, holding a "reverse auction." Nothing good can come from following this advice. Let me explain why. The first premise for this method is that all contractors, and their work, are the same. If nothing else, this is exactly contrary to another basic business principle: Never let your product become a 'commodity.' Successful businesses become that way by focusing on one part of the market, and excelling at it. That's why nobody confuses Macy's with Wal-Mart! Another practice followed by successful businesses is a logical extension of the "80/20 rule." That is, 80% of their business will come from 20% of their customers. Recognizing this, a business will reward regular, reliable customers with their best pricing. That is the customer base they care about ... everything else is just gravy. For an example of this, look no further than the local 7-11 ... that business depends completely upon the folks who stop there every day for their morning coffee, donut, and pack of smokes ... and not the one-time buyer of that $3 can of dog food. What this means is that a 'one time' customer already has a strike against him. The contractor has no idea how the job will turn out, or whether payment will become a problem. He covers this risk by charging more. As for 'calling everyone in the book' .... that's why many contractors will charge for an estimate. They're not stupid; if they realize that they have, at best, a one in fifty chance for the job, they're going to want to get paid for his time. This is especially true if the work you propose is somewhat away from the sort of work they usually do. Finally ... and this may be hard for 'Joe Homeowner' to fully appreciate ... but a large number of contractors are simply not in the phone book. Not even in the white pages. This only means that you'll never find them - without a referral. Far from suggesting that there is something shaky about them, this can mean just the opposite. I know, for example, of one such who has a bond limit way up in the stratosphere, has been in business for decades, and did a major part of the work in my town's tallest building! (This particular guy has scaled back, almost retired, and no longer does big jobs. Indeed, he'd be perfect for a homeowner. Yet. you'll never find him without an introduction!) Anyone who's worked construction has seen them all at work - the good, the bad, and the ugly! Quite often, the most problematic jobs ... jobs that drag on forever, and end with everyone unhappy (except maybe the lawyers) .... are the very jobs where someone was chosen because he was 'cheap.'
All good thoughts. I am not looking for the cheapest bid on this. Maybe I made it sound like I was. Just looking for a ballpark to plan the budget. I don't mind paying good money for good quality but also don't want to be clueless when evaluating proposals. My philosophy with this and the other contractors is to select a great one based on local reputation and the stay the hell out of the way. I will do so with the electrical part as well.
I am reminded of something that happened to me, long ago and far away.... I was overseas, living out of a backpack, and decided that I needed a multi-function knife. On a rare trip into a town, I located one that perfectly fit my needs, and paid for it.
Naturally, every mothers' son I met after the purchase immediately told me how foolish I had been to pay THAT much, had I but asked them, why, I could have found one just as good for a fraction the price!
My reply was that the knife was worth it when I bought it, and was still worth the price. I also made clear that I had the exact knife I wanted ... with the features I wanted -no more, no less- and was not some cheap look-alike piece of junk. My 'advisers' were most unhappy with my response.
I still have that knife. The lesson I learned from all this is that you can't be happy, or get good value, unless you first define your needs. It's quite important that you buy what you want ... and not what someone wishes to sell. We can all recall times we've asked for one thing, only to be offered another. It can be quite maddening; sometimes you want to just walk away, right then! I am please you have not taken my comments personally - they were not meant for you alone! Rather, I try to address the others who will read them, and related issues that keep turning up. To get the right answers, a man needs to ask the right questions!
FWIW in my area those two panels alone will cost you somewhere between $5 - $7K ....but that includes the breakers
and I'm further guessing the 1ø panel will be subbed from the 3 ø power panel..so add another grand for that little feed but only if they are in close proximity to each other and by that , I mean inches apart
aside from that I have no idea if contractors charge per S.F. or flat rate or their gut with a first time customer .!!
.
.
.
, wer ist jetzt der Idiot ?