It Says 100amps But.... - Electrical - Contractor Talk

It Says 100amps But....

 
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Old 07-21-2004, 11:01 PM   #1
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It Says 100amps But....


Just had my service switched from fuses to breakers. Glad I did. Anyways, the main breaker says 100amp but when you add up all the amps on the individual circuit breakers its 165amps (1 30a dbl pole, 3 20a & 5 15a), whats up with this? I wanted to add another 15a circuit, the service handle this?

Also, now my washer and dryer (20a circuit) wont run. The washer lights wont even come on and the dryer cranks very slowly for about 5 seconds and quits but both will run on other circuits. I already replaced both receptacles and replaced the 20a breaker but it still wont give full juice, now what?

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Old 07-22-2004, 07:46 AM   #2
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Re: It Says 100amps But....


Call the electrician that installed it.

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Old 08-05-2004, 08:54 AM   #3
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Re: It Says 100amps But....


That is not how it works. The amount of amp's the panel adds up to isn't the amp service you have. Each breaker is there for a load trip. You're not using all the power at full capacity for each breaker at the same time. If you were the main breaker would be tripping.

As for your washer and dryer problem, I agree tetorbilt " call the electrician " somethings not right. Sounds like a problem waiting to happen.
 
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Old 09-05-2004, 09:14 AM   #4
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Quote:
Originally Posted by Unregistered
Just had my service switched from fuses to breakers. Glad I did. Anyways, the main breaker says 100amp but when you add up all the amps on the individual circuit breakers its 165amps (1 30a dbl pole, 3 20a & 5 15a), whats up with this? I wanted to add another 15a circuit, the service handle this?

Also, now my washer and dryer (20a circuit) wont run. The washer lights wont even come on and the dryer cranks very slowly for about 5 seconds and quits but both will run on other circuits. I already replaced both receptacles and replaced the 20a breaker but it still wont give full juice, now what?

OKT
There is no problem with the breakers adding up to more than the Main. They re basically rated for the wire size of the branch circuits and the Main is rated for the total load. Sounds like the dryer is on 120 instead of 240. I would say it was probably terminated wrong in the new panel.
 
Old 01-10-2005, 07:27 PM   #5
 
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Re: It Says 100amps But....


Quote:
Originally Posted by Unregistered
Just had my service switched from fuses to breakers. Glad I did. Anyways, the main breaker says 100amp but when you add up all the amps on the individual circuit breakers its 165amps (1 30a dbl pole, 3 20a & 5 15a), whats up with this? I wanted to add another 15a circuit, the service handle this?

Also, now my washer and dryer (20a circuit) wont run. The washer lights wont even come on and the dryer cranks very slowly for about 5 seconds and quits but both will run on other circuits. I already replaced both receptacles and replaced the 20a breaker but it still wont give full juice, now what?

OKT
most likly your dryer should be on a 30 amp circut with 10 wire, and your washer a sep circut. you old fuse may have had a penny in it and handled the amps, i dont know. so the electrician not wanting to get in bind (and do his job) took a circut of a 20 amp fuse and slapped it on a 20 amp breaker. or he dropped a leg. and ya got 120 v on 240 dryer.
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Old 12-19-2009, 03:58 AM   #6
 
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Re: It Says 100amps But....


Question.... I may be wrong, but isn't it true when you have a 200AMP main breaker on single phase service that really means that you have 200 AMP per Leg for a total of 400 usable (only up to 200 per side) amps before you will trip the main
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Old 12-19-2009, 07:51 AM   #7
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Re: It Says 100amps But....


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Question.... I may be wrong, but isn't it true when you have a 200AMP main breaker on single phase service that really means that you have 200 AMP per Leg for a total of 400 usable (only up to 200 per side) amps before you will trip the main
It could be said that way, but never is. 200a @ 240v is eqivalent to 400a @ 120v, but it is NOT 400a @ 120v. It is simply 200a @ 240v.

The best and most accurate way of expressing this is a 200a @ 240v service can provide 48,000 watts, or 48kW worth of power.
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Old 12-19-2009, 08:58 AM   #8
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Re: It Says 100amps But....


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It could be said that way, but never is. 200a @ 240v is eqivalent to 400a @ 120v, but it is NOT 400a @ 120v. It is simply 200a @ 240v.

The best and most accurate way of expressing this is a 200a @ 240v service can provide 48,000 watts, or 48kW worth of power.

I use a plumbing analogy to explain this.

Go to any sink in your house and measure the pressure in the hot pipe and the cold pipe. Let's say the hot pipe measures 60 psi, and the cold pipe measures 60 psi.

This does not mean you have 120 psi of water pressure in hour house.

As for the OP, you could legally have enough breakers to add up to 1000 amps if a proper load calculation had been performed and it would still be legal and OK. The term is 'load diversity'.

This means not every circuit is opertaing at 100% of it's capacity 100% of the time. For instance, right now, what is the load on your refrigerator circuit? If it's not running, then it would be 0 amps.
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Old 12-19-2009, 09:26 AM   #9
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Re: It Says 100amps But....


Op is 5 years old. Is this a new record for a resurrected thread?
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Old 12-19-2009, 09:34 AM   #10
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Re: It Says 100amps But....


On some forums it is advised to post a new question in an existing thread. I don't like it, but a lot of people do it.

We had someone recently say he had never heard of starting a new thread if one existed with a similar topic, and that every forum he went to was like this. I hardly ever see this though. Weird.
I can see threads with hundreds of posts and a LOT of confusion that way.

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