Garage Power

[triplethreat]

Okay I'm thinking out loud here. Anyone feel free to chime in. I called my Electric company today BGE and told them that I was building a 2 story attached garage via a 54 long breezeway. I asked them about putting in a meter at the garage, They said it would be considered commercial and they would charge me more money for my electric. Okay so lets upgrade the service at the house instead.

I've got 2 existing 200 amp panels but I'm don't think it has enough available power to run everything I might want in my garage. Heat pump, Welder, Lift, Air Compressor, Tons of lighting, Powder Coat over and the list goes on and on. I'm thinking I've got 75 amps at best. My understanding is only 80 percent of 200 and I've got a 50 amp circuit for the hot tub plus several circuits for the new kitchen and a few others. So I applied online to upgrade my service from 400 to 600 amps. What I'm hoping to happen is that I can install another 200 amp panel in the house and run some sort of wire??? to a 20 circuit panel in the garage. I hope to run this wire under the roof section in the breezeway. So what kind of panel would I install in my basement? Just some sort of 200 amp breaker? Would I then run a 4 conductor service type wire guessing about 3/0 copper or 250 kcmil Aluminum approx 85 feet to a 20 circuit panel in the garage. Can I run this through PVC under the roof in the breezeway? Would this panel need a 200 amp breaker as well or just the typical branch circuit breakers. I've got the new 2008 NEC book and wow lots of information. If only I understood it Trying to build the ultimate guy cave with champagne taste and beer bottle pockets. I'm new to this forum, but have gotten some great information from it. Just wanted to say Thanks in advance. Don

 

[Aceman]

You would probably save money by paying an electrician for a consultation.

How's that expression go? "The cheapest person spends the most."

 

[triplethreat]

I guess I was hoping that their might be an electrician or two on this forum that may have some sound advice. Knowledge doesn't always come with a price tag, but I will consider the suggestion. Food for thought. Not every electrician is going to offer the same advice. (Good or Bad) So how does one know which one to choose and at what expense?

 

[dodgeram2500]

Buy / bum an amp clamp from somebody. Turn everything on in the house that you'd have on during max load. See how little you actually draw.

How many people will be working in your garage at any given time?

 

[mrb]

I guess I was hoping that their might be an electrician or two on this forum that may have some sound advice. Knowledge doesn't always come with a price tag, but I will consider the suggestion. Food for thought. Not every electrician is going to offer the same advice. (Good or Bad) So how does one know which one to choose and at what expense?

give it a couple days, you will have plenty of feedback including a few tips from qualified individuals.

You are off to a good start by asking first before you randomly started working on it. More than once have people started out, bought materials, done a ton of work, only to find out they did it all wrong.

 

[mrb]

I bet 100amps will do you fine for the new garage. I would take a look at the two 200a panels, and see which one has the smallest load on it, and feed a 100amp main breaker panel in the garage from it.

You will find that upgrading past 400amps is going to get really expensive as you will have to switch to CT metering.

 

[triplethreat]

What is CT metering? I put in a request to BGE my power company. My understanding is they will put the new meter in for free. I just need to have everything else ready. I'm currently studying to take a test so I can become my own electrician so I can apply for permits just for my house. Just got the book a few days ago so I've got a ways to go. At least the test is free and open book and only 25 questions. I'm sure they are going to be challenging. Everything in my house is electric. No gas of any kind. I've got so much computer hardware in my basement office that I don't even need to heat it. However in the summer time alarms so going off If I don't turn on the AC. My shed as a bunch of power tools big saw, plus AC, electric heat dehumidifier also some loud computers. I've got 3 20 amp circuits just feeding my shed. I've got a clamp on amp meter and will see what I can come up with. My one panel is stuffed to the rim while the second panel has a few open spots but also has the hot tub which alone is a 50 amp breaker. The Dishwasher, Shed, 6 outside lights 300 watts each around the house, pump for the pond and a few outlets in my other attached 2 car garage plus a few others. I'm guessing with everything running I've got to be pulling 125amps? I thought you didn't want to go over 80 percent of the capacity thus I figure add a 3 service panel. My one UPS in my computer room is on a dedicated 20 amp outlet. The other 2 UPS's are on 15 amp circuits. Looking forward to reading what other people have to say. Thanks for the advice of the clamp on amp meter If time permits I will try it over the weekend.

 

[2level]

If you get approved by the POCO for 600A service (400A is the max residential in my area) and if you ask (try to get their business cards / email) the local electrical inspector will tell you the preferred conduit type and wire specs. I'm a do it yourself man. In my city the electrical inspector provides good customer service and is great about answering emailed questions. He'll put an approval or rejection of my proposed method (or code clarification questions) in writing.
If your not in a hurry and patient enough to learn all the details, you can do it yourself.
But like Aceman advised, a consultation with a pro is always good. If you DIY, check out a code summary book to compliment your NEC2008 code book. I picked up one at HD for about $15. It's called Code Check Electrical by The Taunton Press. Good luck.

 

[mrb]

CT metering is current transformer. This is what is required for anything over 400a. Just the main cabinet for it is between $1200 and $3000.

the 80% rule is for continuous loads. For example on your spa, the heater isnt running 24/7 it cycles on and off. Add up everything connected to that second panel and see where youre at.

 

[walrus]

You don't add up the values of your breakers to figure load. Just because you have a 20 amp circuit to a UPS doesn't mean the load is 20 amps. When are you going to have everything running at the same time? Never would be my guess

 

[PAToyota]

Biggest problem with asking such questions on this board is that the results vary from location to location depending on the local electric companies policies.

That said, if you were my neighbor and trying to do it here, a second meter to a property would have to be a commercial meter (you cannot have two residential meters to a property) and 400amp service would be the maximum residential service.

 

[tfi racing]

IMHO,I doubt that you will ever use 200A yet alone the 400A that you have!
Unless your house is about 20,000 square feet with full electric heat and AC,three or four kitchens with ten people living in it of course.Then again,I do come from an area with gas as the preferred method of space heating(Alberta),the last house I saw a 400A service in was worth about five million dollars and about 15,000 square feet,its hard to imagine a 600A residential service.Before committing to such an expensive project it would be a good idea to first measure how much current you are actually using as some have suggested,you may be surprised at how little your home really uses.

 

[StumpFJ40]

400 amps is ALOT of juice! Just from what you've stated, you're probably not coming close to using that much at once now. Why does your home have 400amp service to begin with? do you have electric baseboard heat? On demand hot water?

What are your electric bills like? Not necessarily a good judge of amperage requirements, but does speak to usage and need for large capacity.

I say split 150 amps off... that should be more than enough with 250 left for the house incase the wife has the washer, dryer, dishwasher, thermostat pinned at 80, baking a lasagna while running the garbage disposal and drying her hair while the dog kicks with his ***** in the hottub... oh and every light is turned on in the house.

 

[OldCarGuy]

I would imagine that a 400 Amp service would be more than enough power. My Garage complex has a single remote 400 service. From that I feed my home’s 200 AMP load center. My 30x50 garage machine shop has a 200 Amp load center. Plus three other free standing garages each has their own 100 Amp load center.

Remote 400 Amp meter.. I ran all the wires underground from there..

My Complex...

 

[triplethreat]

Okay Okay I give up. You guys have beat me into submission. An electrician had me add the second 200 amp breaker to support all of the following goodies. The electrically heated shed with lots of wood working power tools for me and the misses. I've built a several thousand gallon fish pond with a multiple pumps motors big heater for the winter time and lighting. Also at the time I had a swimming pool and I added a 50 or 60 amp hot tub. Plus I would like to be able to plug in my RV which has a 50 amp plug on it as well. Not sure what BGE is going to do. I was just trying to plan for the worst case. Two guys working in the garage. People upstairs playing pool. The AC is running. I'm lowering the lift the air compressor kicks on while my buddy is welding. The lights are cranking then the frig upstairs kicks on. So how much power am I pulling? Let alone a radio and computer are running which is nothing. Like I said before I heat my computer room/ office with the hardware that I've got running. I use to keep about 12-18 computers running but have since scaled back to 4 plus a disk array. When my office hits over 90 in the spring you know the computers are throwing off some heat. I tend to try and over kill projects. My electric bills run about twice that of my neighbors with the same size house and they have one more kid. Hopefully over the weekend I will dig up my clamp on amp meter and see what I can come up with. Hey if 400 amps works I'm a happy camper. I still think I'm cutting it close but again I'm happy to be wrong.

I'm heading to see the builder tomorrow to give him a deposit. Garage should look something like this...I saw this driving down the road mine should be about the same.

 

[triplethreat]

Some more picks of the drive by garage..

 

[sberry]

I agree with others here, its likely the place would run on 200. I have 400 but mine would run from 200 ok. In 30 yrs I can count on one hand the times I have really seen overloaded services. One being an all electric appliance house running on 60 and another on a tavern where someone hadn't really laid out the loading as good as it could have been.