Dumb electrical question

1

1ebo

Member
So I have asked 2 people this question, and haven't gotten a straight answer.

I have a 100-amp circuit breaker box, with the main breaker being 100-amp obviously
I am using 6000 watts at 240v, but I live in the US, so the rest of my house is of course 120v.

My question is: is my main breaker rated 100-amp at 120v or 240v?

I realize this may be a question of "well it depends on what kind of line is coming in?", but generally speaking, which of the two is it?
 
phillipchristian

phillipchristian

New Member
I think you are really confused about electricity bud just from the way you are wording this. Your house is 120/240v (Both) and some of the appliances (a/c, heater, water heater, etc..) are running on 240v current. Other appliances and outlets are running on 120v current. The main breaker (service disconnect) is a 240v breaker as your panel is being supplied with 240v power that is split on the panel. Appliances use the rated amps listed on them or in their manual. If you have a 100amp board then you can only pull 100amps off of it. People try and put larger loads on 240v becuase it uses less amps. If you have a specific question about doing something then post it here and we'll try and help.
 
A

alotapot

Active Member
100 amps IS 100 amps, that is the total limit of amperage that can pass through your panel... regardless of what voltage that amperage is being applied.

alp
 
1

1ebo

Member
phillipchristian said:
I think you are really confused about electricity bud just from the way you are wording this. Your house is 120/240v (Both) and some of the appliances (a/c, heater, water heater, etc..) are running on 240v current. Other appliances and outlets are running on 120v current. The main breaker (service disconnect) is a 240v breaker as your panel is being supplied with 240v power that is split on the panel. Appliances use the rated amps listed on them or in their manual. If you have a 100amp board then you can only pull 100amps off of it. People try and put larger loads on 240v becuase it uses less amps. If you have a specific question about doing something then post it here and we'll try and help.
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Thanks for the follow up/patience guys. I'm actually a lot less confused than I am coming off. I get pretty much everything you are saying.

My very specific question right now, is when I am using 30amps at 240v, assuming thats the only thing on in the house, is that using 30% of my total power capacity, or 60% of my total power capacity? I'm thinking of scaling up marginally, to 8000W, but if thats going to put me at 80% usage, I'll need to use a flip-flop setup instead.

Sorry, I realize I'm probably just asking the question wrong due to ignorance of electrical stuff.
 
M

mydixiewrecked

New Member
you have 240 volts coming into your 100 amp main, the 120volts circuits are made up by using 1 leg of that 240 and a ground.half of 240 is 120. the circuit starts at the breaker which is rated for the specific amps.so to answer your question,your main is rated for 240 volts, if you take the sum of all the breakers currently in the panel, that will tell you how many amps your currently using.
a breaker that has 2 legs is using 240volts, like your dryer/oven,pools,jaccuzzies.
 
1

1ebo

Member
Gr0wGreen said:
call any electrician. no one here wants to be responsible for burning your house down mate. :\
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I hear ya, I wouldn't give out any advice that would have potential for damage either, but this is actually just the planning phase, and will actually determine whether or not I need an electrician. If I end up going the flip-flop route, I can just set that up myself; but this is much more logistically challenging for me, I'd rather just drop in another 30amp/240v drop if possible.
 
1

1ebo

Member
mydixiewrecked said:
you have 240 volts coming into your 100 amp main, the 120volts circuits are made up by using 1 leg of that 240 and a ground.half of 240 is 120. the circuit starts at the breaker which is rated for the specific amps.so to answer your question,your main is rated for 240 volts, if you take the sum of all the breakers currently in the panel, that will tell you how many amps your currently using.
a breaker that has 2 legs is using 240volts, like your dryer/oven,pools,jaccuzzies.
Click to expand...
Ok, that is definitely what I looking for! Thanks for that, only problem is now I have an even dumber question..

If I understand correctly, amps are amps, and if you draw 50amps at 240v or 50amps at 120v, your main 100amp breaker sees that as the same amount of power (obviously the power company doesn't).

Does this mean that if you were theoretically using all 240v outlets in your house, you could use twice as much without tripping the breaker? Are there any other risks associated with that?

Like I said before, this is all theory, no action will be taken without my electrician's involvement!
 
TruenoAE86coupe

TruenoAE86coupe

Moderator
8000 watts is probably advisable to do a flip box, can actually get away using fewer ballasts this way also.
An amp is not an amp. In theory you could pull 80 amps off of each of 2 120 "legs" or 80 amps 240. To truely trace out who goes to which leg and how much amperage is on each leg is a giant pain in the ass. So it would be easiest to just get the flip box.
 
phillipchristian

phillipchristian

New Member
1ebo said:
Ok, that is definitely what I looking for! Thanks for that, only problem is now I have an even dumber question..

If I understand correctly, amps are amps, and if you draw 50amps at 240v or 50amps at 120v, your main 100amp breaker sees that as the same amount of power (obviously the power company doesn't).

Does this mean that if you were theoretically using all 240v outlets in your house, you could use twice as much without tripping the breaker? Are there any other risks associated with that?

Like I said before, this is all theory, no action will be taken without my electrician's involvement!
Click to expand...
First off, remember that you are never supposed to use more than 75-80% of the rated load of any circuit. That means that if you have a 100amp panel you should never be using more than 80amps at 1 time. Also, just becuase a breaker is rated for 30 amps doesn't mean you are using 30amps. Breakers are also oversized based on the 75% rule or more.

Running something at 240v just allows you to do so while using less amps. For example...a 1000w ballast uses 5 amps when wired 240v and 10amps when wired 120v. It uses less amps at 240v because it is essentially being fed those amps at twice the speed.

If you are looking to do a FLIP then you will be using the same amount of amps in your flower room. The only difference is that instead of using 30amps for 12 hours a day you are using 30amps for 24 hours a day. This is why people use FLIPS; to get around the limitations of their electrical service.
 
M

mydixiewrecked

New Member
phillipchristian said:
Running something at 240v just allows you to do so while using less amps. For example...a 1000w ballast uses 5 amps when wired 240v and 10amps when wired 120v. It uses less amps at 240v because it is essentially being fed those amps at twice the speed.

.
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actually it uses 5 amps per leg, 2 legs of 120 using 5 amps each, the speed of an amp is regulated by the size of wire.
 
phillipchristian

phillipchristian

New Member
Just be real careful with the advice you take on this forum regarding electrical installations. Some people are just trying to get their post counts up and others are just here to try and be annoying. Best of luck to you.
 
A

alotapot

Active Member
phillipchristian said:
Just be real careful with the advice you take on this forum regarding electrical installations. Some people are just trying to get their post counts up and others are just here to try and be annoying. Best of luck to you.
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Now that right there is sound advice!

alp
 
D

Dubdeuce

Well-Known Member
1ebo said:
Thanks for the follow up/patience guys. I'm actually a lot less confused than I am coming off. I get pretty much everything you are saying.

My very specific question right now, is when I am using 30amps at 240v, assuming thats the only thing on in the house, is that using 30% of my total power capacity, or 60% of my total power capacity? I'm thinking of scaling up marginally, to 8000W, but if thats going to put me at 80% usage, I'll need to use a flip-flop setup instead.

Sorry, I realize I'm probably just asking the question wrong due to ignorance of electrical stuff.
Click to expand...
30 amps is 30 amps regardless of what voltage you are pulling it through. If you were running the same item at 30 amps on a 240 and somehow switched it to 120v, yes you'd be running 60 amps to achieve the same result. 240 volt allows you to run half as much amperage as a 120volt to achieve the same wattage output.

If you scale up to 8000 watts from currently 6000 watts at 30 amps and you use 240volt equipment again, you will only raise about 10 or so amps. If you use 110 equipment from 30 amps, you will use over 20 amps to achieve the same wattage. Either way, on 100amps and only 30 used, scaling up a couple thousand watts sounds like you have plenty of room.
 
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