Hey All - got a question about something thats been bugging me tonight
(dont worry im *not* going to do this, im just interested to know if
Is there any difference between a 30 amp breaker (2 hots, one out of
each pole of the breaker), and two 15 amp breakers, one hot coming out
ie, if you wired a 30 amp plug, would both of the above equate to the
What problems would arise, etc?
sorry if its a dumb question :)
: > Hey All - got a question about something thats been bugging
: > (dont worry im *not* going to do this, im just interested to
: > its possible).
: > Is there any difference between a 30 amp breaker (2 hots, one
: > each pole of the breaker), and two 15 amp breakers, one hot
: > of each?
: > ie, if you wired a 30 amp plug, would both of the above
equate to the
: > same thing?
: > What problems would arise, etc?
: > sorry if its a dumb question :)
: It's a dumb question.
NO, it's not. The only dumb question is the one that doesn't get
Well electrically it should be the same but separate breakers won't trip
off together unless linked which may or may not be possible.
By plug I presume you mean receptacle. The problem that would arise would
be someone going to work on it or equipment plugged into it might only
switch off one leg and get a nasty surprise. This might be ok in a
temporary situation with outlet and both breakers suitably labeled but
nothing you'd want to do permanently. Labels fall off and people leave,
forget or simply don't understand the concept.
This is Turtle.
Your Question is just cloudy to understand.
A 30 double Breaker hooked up and you can pull 2 -- 30 amp circuits off
of it for 220 service or 2 - 30 amp single circuits or 2 single
circuits to the house.
A 15 double Breaker hooked up and you can pull 2 - 15 amp circuits off
of it for 220 service or 2 - 15 anp single circuits or 2 single
circuits to the house.
No a 30 amp Double circuit and a 15 amp double circuit would not be the
same as to what it would do or let mess up using one or the other. If
you hooked up a 15 amp appliance to a 30 amp circuit. it could burn the
appliance up and the house too but still not trip the circuit breaker.
So a 30 double breaker circuit and a 15 amp double breaker circuit is
not the same.
Yeh, there are three differences.
1) A 30a 240v breaker (I think that is what your are referring to) puts out
30a 240v. Your pair of 15a 120 breakers put out either 15a 240v or 30a 120v
(or even 0a 0v) depending on how your circuit was.
2) The 240v breaker will trip both sides simultaneously; the pair of 120v
3) The 240v breaker can't be put in the circuit box stupidly (see previous
question); the pair of 120v breakers can.
Don't use the 120v breakers for 240v.
And if you have to ask this question, thing about whether you really want to
do this project yourself.
Oops I misread your post and thought you were using the two breakers of the
same value on different legs in place of a double breaker. That would
indeed be electrically the same though not a good idea for reasons cited.
As for the question you really did ask a 30 A two pole breaker would pass
30 A on each leg, not 30 total. In 240 or 208 V usage 30 A would be going
out one line and back the other so still just 30 total as it's across two
hots. Naturally 30A breakers would not offer proper protection on a 15 A
And on the 2nd question two individual 15 A breakers would not suffice to
feed a 30A recepticle.
little 15 amp wires carry 15 amps
big 30 amp wires carry 30 amps.
giving little wires big amps makes big fires.
never mix or match any unmatched wires to their breakers.
if you do you put the next electrician at risk.
Yes, there is: the former supplies one 30A circuit at 240V, or two 30A
circuits at 120V, depending on how it's wires, and the latter supplies two 15A
circuits at 120V. The latter can be combined to supply one 15A circuit at
240V, if you know what you're doing -- and you don't.
Risk of fire, chiefly.
Yes, it is.
Doug Miller (alphageek at milmac dot com)
In the end, yes. But I can see where someone might think a double breaker
with a single handle that has "30" written on it is composed of two 15A
breakers, not two 30A breakers. It's wrong but it wasn't pulled out of
thin air; there is a logic to the wrongness. So not all that dumb a
Here's a distantly related question. Is it ever permissible to use a two
pole breaker for two 120V circuits not for 240/208? Let's say someone
wanted to ensure that when circuit is turned off or tripped the other is
off as well. Maybe for some equipment that for whatever reason has two
120V feeds and you wish to enforce that it's completely dead.
Sure, why not? It is commonly done on multiwire circuits, though one might
call that a 240v.
I have a duplex breaker that lets you put either two 240v breakers in the
space of one normal 240v breaker, or one 240v breaker and 2 120v breakers;
depending on whether or not you remove a handle tie.
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