Meaning Of 150 amp Service: At 115 V, Or At 220 V ?

[Robert11]

Hello:

When they say a house has, e.g., 150 amp service, is that 150 amps at 115 V, or

150 amps at 220 V ?

Thanks, Bob

[jhill]

[TCS]

Yes. And by the way, it's the same thing. If you have two 115V lines @ 150 amps, it's also 150 amps @ 220V.

[Hello World]

What are inside the feed wires? 2 hots @120V each, and a neutral? The neutral and ground are usually connected at the panel. So how the electricity figure which way to go, to the neutral, or to the ground?

[EL]

Short answer is "yes" ;^)

A home with reasonably modern wiring will have electric service with 3 wires: 2 hots and a neutral. You'll get 220 (or thereabouts) across both hots, and 110 (or thereabouts) from either to the neutral. Both hot wires go thru the main breaker, which is really two breakers connected together mechanically so if one trips the other does also.

Bottom line: if you're using 110V you can draw 150 amps off each leg (300 total if evenly distributed), if you're using 220 you can pull 150 amps total. In the real world you're probably using a mixture so it gets a little more complicated.

Eric Law

[Matt]

It figures it out by asking the water. That's what the wire is for that connects the panel to the water pipe - it's a communication link.

[bill a]

is that way power is measured in watts? because it goes thru watter?

[Matt]

Yep! Thats it exactly!

[Nehmo Sergheyev]

- Hello World -

- Nehmo - For simplicity, let's only concern ourselves with _one_ hot (black), the neutral (white), and the ground (bare or green). Also let's just consider an instant in the changing Alternating Current (AC) cycle, when the hot is conventionally-called positive. Electricity of the household line-current type can only travel in a complete circuit ? the circuit has to form a loop. So if a load, a lamp (a lamp with a metal housing that is grounded to the ground prong of a 3-prong plug) for example, is placed between the hot and the neutral (the normal situation), the electricity goes, from the panel, through the hot, through the lamp, then back through the neutral back to the panel. The ground wire does nothing because there is no complete circuit that includes the ground wire.

But suppose something goes wrong: let's say an insulation-stripped hot wire inside the lamp now touches the lamp housing, a short. Now when you turn on the lamp, which allows current to the hot wire, the electricity goes from the panel, through the hot, through the short to the lamp housing, through the ground prong of the plug, through the ground wire, and back to the panel where, since the resistance of the circuit is low and the current is thus high, the breaker opens. The ground wire served its purpose.

That's how the electricity knows where to go; it goes only where the circuit is complete.

[TURTLE]

This is Turtle.

150 amps in 115 volt service or 300 amps in a 220 volt service.

You can have 15 --- 20 amp single 115 volt breakers or 7.5 --- 20 amp double pole breakers at 220 volt service.

E-mail me if you want to discuss it.

TURTLE

[Ross Mac]

How do you figure???????.........Ross

[Doug Miller]

WRONG. It means 150 amps at 220 volts.

Wrong again. It's perfectly OK for the ratings of the individual branch circuit breakers to add up to a *lot* more than the rating of the main disconnect. This is because the branch circuits will not _all_ be in use, at full capacity, at the same time.

The OP would be better off posting his questions publicly so that others have the opportunity to correct your errors.

-- Regards, Doug Miller (alphageek-at-milmac-dot-com)

Get a copy of my NEW AND IMPROVED TrollFilter for NewsProxy/Nfilter by sending email to autoresponder at filterinfo-at-milmac-dot-com You must use your REAL email address to get a response.

[willshak]

On 1/20/2005 8:40 AM US(ET), Doug Miller took fingers to keys, and typed the following:

I certainly hope so. I have a 200 amp panel, and if I add all the breaker sizes up (including the double 220v ones), it comes to 660 amps. Just the 20 amp breakers alone add up to 280.

[Lawrence Wasserman]

Yes.

That is, if you look at how 220 is wired in a (US) home, if 150 amps is being supplied on one leg, then it can "return" so to speak, either on the neutral for 110V, or on the other hot leg for 220. So the 150 amps is available at either voltage.

[Matt]

Give 'em hell, Doug!

[Doug Miller]

No.

WRONG. 150 amp service can supply 150 amps on *each* leg of the service. That adds up to 300 amps at 110 V. Or 150A at 220V. Or any combination that adds up to 33 kVA, provided that no more than 16.5 kVA flows through an individual leg.

[default]

hots and a neutral. You'll get 220 (or

Both hot wires go thru the main breaker,

other does also.

evenly distributed), if you're using 220

it gets a little more complicated.

This answer being for most of north america, assuming that you don't specifically ask for something different, in areas where 208V residential service is also available, and assuming you're willing to tolerate a little laxity of of terminology.

What you're actually getting is a nominal 33 Kilowatts, which can manifest as 150 amps at 220V, or 300 amps at 110V, or any pro-rated combination between.

[Ross Mac]

Thanks Doug...thats why I posted the "How do you figure" comment...there was a serious violation of ohms law in the Turtles comment....Ross

[bluemax1811-newsgroups]

Ah, a man that knows there is a difference between kVA and KW. You ought to use a moniker of "Mr. Power Factor" and keep 'em guessing. ;-)

Best regards, Bob

[trader4]

Yes, but is he real or reactive?