# How many amps coming in on one 120V leg from the pole?

About how many amps are coming in on one 120V supply leg from the pole?

Amperage does not “come in”. It depends on the load.

Bingo!

Kenton, you only have one of the two measurements needed for the formula.

AxV=W

Since you’re asking about the service coming in off the utility pole, the only breaker is the fuse at the transformer, or the wire itself. So total amperage available is what the ampacity of that size wire is, or the fuse at the transformer, whichever is less.

So… what’s common? I guess I’ve seen skinny wires for old 100 amp services and bigger sizes for 200 amp services. To be honest, I just looked for problems like contact with branches, not consistent conductor size.

I’m researching Australian residential electrical systems (which inspectors there do not inspect at all, something that I intend to change) but in googling “Australian electrical systems” I get a response that their residential systems are limited to 10 amps, even though supply from the pole is 240 and 50 Hz. According to what you guys tell me, can that be limited by conductor size? I’m guessing no, only that conductors will overheat if overloaded.

So I’m in the early stages of trying to figure out Australian residential electrical systems, even though it brings up more questions about US electrical systems.

Is this what you are refering too? I think they mean individual branches of residential circuits are 10amp.

The normal maximum current capacity is 10 Amps, but 15 and 20 Amp plug and socket combinations are available, when used with appropriately rated sub-circuits.

http://www.britzinoz.com/info/electric.htm

Electricity supply in Australia

Normal Household Electricity is: 240 volts, 50 Hz, 10 amps max.
The normal mains voltage in Australia is 240 volts, but this can vary between 216 and 254 volts depending on time and load conditions in the distribution system.
The normal maximum current capacity is 10 Amps, but 15 and 20 Amp plug and socket combinations are available, when used with appropriately rated sub-circuits.
The operating frequency is 50 Hertz
www.acma.gov.au
It is very common for new migrants to bring a few British 4 or 6 gang extensions, and change the single plugs on those, to an Australian one, to start of with.
Australian Plugs do NOT have fuses, but are limited to a 10 Amp supply.

Amps X volts = watts (Kilawatts) Watts is what you pay for;-)

Hey, I agree, the further up the ladder you climb, the harder you hit after you jump. What’s this got to do with my question?

This is where I started my research, David. It’s not answers.

I think a lot of you guys might listen to Chris and Michael.

I agree with David the 10 amp number is for branch circuits not the entire system ampacity in the house. Even at 230 volts you cannot run much in a dwelling at only 10 amps.

If you want high capacity than you can use more amps like 3 or 5. If you want less then go for 2 amps.

I believe if you are referring to the potential amperage that can be provided by the utility company, the number is virtually limitless.

Southern California Edison (SCE) uses these standards

Jeff, those numbers are used to coordinate short circuit fault protection interrupting rating. The service equipment needs to meet or exceed the available current.

It’s a strange question.

I agree with Jeff. There really isn’t much limiting what is available from the service drop. It’s the service OCP which provides the limit. For a U.S. 240 volt 200 amp service, that would be 200 amps on each leg or 24,000 Watts rated capacity on each leg (48,000 Watts combined).

If the stated Aussie limit of 240V @10Amps is for a service, that’s only 2,400 Watts. That would be the equivalent of a 120V 20 amp branch circuit.

I think the numbers that you are reading apply to typical lighting and outlet circuits, not the service

I’m not sure there is a “common”. As you know, most residential breakers in the US are 100 or 200 amp.

There are no amps until there is load applied. Voltage is always present, like the water below your faucet handle. Voltage is pressure, amperage is flow. So the pressure (voltage) is there waiting, and the flow (amperage) is determined by the load, like how you turn the handle on the faucet farther for more flow.

Hope this makes sense

Understood.

I’m not sure if I followed the question accurately, but it looked to me as if he was asking the potential amount of current that can be supplied from the utility company, which is virtually limitless.

You will find residential panels with 10K and 22nd AIC, amps interrupting capacity.