Upgrading Residential Service

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  #1  
Old 08-22-06, 10:32 AM
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Upgrading Residential Service

Other than replacing the breaker panel, what else is involved (hardwarewise) in upgrading residential service from 100 to 200 amps? The house's electrical system is of modern construction (Romex with ground wire, 3-prong outlets, GFCIs in bathrooms, etc.). The existing panel is a Square D. There are no breaker slots left, and I need to add some circuits for a workshop.
 
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Old 08-22-06, 10:53 AM
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The panel may not have to be replaced. The lines from the street to the meter may or may not have to be replaced. The lines from the meter to the panel may or may not have to be replaced.

You may not have to change the panel to go to 200 amps, it may already be a 200 amp panel (unlikely, but it is a possibility).


Do you need 200 amps? If you don't need 200 amps, then consider either a sub panel, possibly in the workshop, or consider mini-breakers.
 
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Old 08-22-06, 11:23 AM
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Answer Bob's questions as well as these: Which Square D panel is it? QO? Homeline? Is the house air-conditioned? Do you have gas dryer and range or electric? What other significant electrical loads do you have? What significant loads do you need in the shop? Welders?
 
  #4  
Old 08-22-06, 01:07 PM
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Thanks for the replies. This actually relates to a house I plan to purchase so I don't have immediate access to answer some of these questions. I'll do so as soon as I can.

Other than my wife's kiln (30-amp circuit) I don't intend to have any large loads like welders. Mostly just a 110 VAC table saw and some outlets for small power tools like routers, sanders, and such (the area where I want the shop has no outlets at all now).

As for the other loads, the range and dryer are both electric. Heat is oil-fired hot water. Air conditioning is three or four 110 VAC window units in various rooms.
 
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Old 08-22-06, 01:40 PM
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As to "what is involved", I suggest you obtain quotations from local EC's on the cost of an "up-grade" to 200 amps.

I do not imply that such an up-grade is necessary at this time. A definite answer requires a "service calculation" which is based on the the existing connected loads , and any "to-be-connected" loads.

If you need space-provisions for additional circuit-breakers, it's possible to install, directly next to the existing Service-panel , a Sub-panel equipped with a 200 "Main" breaker. This Sub-panel is connected to a 100 amp "Feeder" between the old/new panels, protected by a 100 amp breaker in the Service panel.

The advantage to this arrangement is that if in the future you up-grade to 200 amps, the 200 amp Service-panel is already "in-place".

Good Luck, & Learn & Enjoy from the Experience!!!
 
  #6  
Old 08-24-06, 09:09 AM
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Thanks for the info and suggestion. I am going to get quotes for this work. I just wanted, if possible, some sort of idea of what's involved.
 
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Old 08-24-06, 09:29 AM
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Talking

Generally, aside from the breaker panel, the meter base and either the service riser or downpipe must be changed when upgrading from 100 amps to 200 amps.

As PAATBAA said, you may or may not need all of this done. The size of the wire determines the size of the service and also determines the size of the pipes such as the riser or downpipe. Additionally, some municipalities enforce their own codes as to size minimums on risers and other things.

If you get a quote from an EC you can ask them to break it down for you.
 

Last edited by Professor; 08-24-06 at 09:46 AM.
  #8  
Old 08-24-06, 02:04 PM
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As others have mentioned there are cheaper and easier ways to get just a few extra breakers. However if you want to start fresh this is what's required in this little part of the world ...

First get quotes from electrical contractors for the inside work and whatever is required to the meter. Simultaneously contact the utility and get a quote to upgrade the wiring from the transformer. Also get a quote from the utility to convert to underground if that's of interest.

If the existing feed from the transformer & service entrance cannot handle the load, then as soon as practical, you sign the utility agreement and pay the utility company to get on their project list. Then you schedule the electrician. The contractor upgrades the panel to 200A and they provide any temporary connection needed between the "demarcation" and the transformer. For example, a temporary weatherhead jury-rigged to a new underground pedestal. The contractor breaks the meter seal only AFTER the utility has been advised.

After checking the contractor's work, the municipal inspector issues an upgrade certificate directly to the utility. The utility will then upgrade their part and seal the meter.

If you're upgrading panels make sure you get a 42-circuit panel. Cutler Hammer makes a load center specifically for the upgrade market which has connection buses near the top for shorter existing wires. Not sure if it's worth a lot more money but it's worth considering.

Also if you're the type that likes to work in your own panel, consider a meter pedestal with a breaker or shutoff switch so you can completely de-energize the load center.
 
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Old 09-20-06, 07:38 AM
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Well, we're finally in the house and I've had a chance to take a closer look at the breaker panel. It's a Square D type QO. There are no unfilled slots, but two are filled with a double 30 amp breaker and the legend doesn't say what that's for. The only 220 loads are the dryer and water heater, which I know are on other breakers. So maybe I do have a couple of slots. I'll pull the cover and check.

Is there some on-line source for information on how to do a service calculation? I haven't found anything yet that didn't cost money. I'm an electrical engineer but this residential stuff is kind've out of my area of expertise.
 
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Old 09-20-06, 07:42 AM
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Originally Posted by md2lgyk
...Is there some on-line source for information on how to do a service calculation? I haven't found anything yet that didn't cost money. ...
Shoot me your E-mail and I'll send you back one of my local forms. This forum doesn't let me do attachments.
 
  #11  
Old 09-20-06, 07:49 AM
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www.Electricalknowledge.com has a residential load calculator that you can access for free.
steve
 
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Old 09-20-06, 08:07 AM
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Remember, do not post an email address here, use a provate message.
 
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Old 09-20-06, 09:15 AM
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Originally Posted by hillbilly ace
www.Electricalknowledge.com has a residential load calculator that you can access for free.
steve
Excellent, thanks.
 
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Old 09-20-06, 09:16 AM
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Originally Posted by MAC702
Shoot me your E-mail and I'll send you back one of my local forms. This forum doesn't let me do attachments.
I've sent a PM.
 
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Old 09-21-06, 07:08 AM
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Thumbs up

Originally Posted by racraft
Remember, do not post an email address here, use a provate message.
Sorry, I didn't know....guess that I should re-read the rules (that's a tongue twister).
steve
 
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