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barry martin
 
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Default 15 or 20 Amp

David:

DD I would like to put my computer equipment on its own circuit. Would I need
DD a 15 or 20 amp breaker to do this? Are there any restrictions as far as ho

DD many breakers can be in the box? I know there is room for more. What gaug

DD wiring would this require?

I'd go with the 20 Amp circuit "just because" it's a little more
robust in case you need more current later. Maybe it's a little cool
in the Computer Room and you need to take the chill out by running an
electric heater.

And for your next question, no, you do not have to use 20A rated
outlets on a 20 Amp circuit - the 15 Amp duplex outlets are fine.

BTW, speaking of outlets, you might want to have a few more than one
or two per wall for the equipment. Also plan ahead to position the
outlets where you need them now and where you may need them int he
future should you re-arrange things. Easier and cheaper to plan ahead
for the future now.

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  #2   Report Post  
Greg
 
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The bull**** is certainly flying around here.
Take a look at 310-16 in the NEC and you will see that 14ga wire is really
rated at 20a. . Article 240.4(D) limits the O/C device to 15a so people who try
these "run it till it trips" experiments or lifestyles are not really creating
a hazard. If you can load a 15a breaker/14ga copper circuit enought to warm the
wire you have a defective breaker.

  #3   Report Post  
Greg
 
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Default

If you can load a 15a breaker/14ga copper circuit enought to warm the
wire you have a defective breaker.


Breakers are NEVER defective? That's good to know! Thanks!!!


If you have a defective breaker it doesn't matter how big your wire is.
Available fault current in a home is in the thousands of amps. (only limited by
the size of the service drop)
That was not the discussion.
  #4   Report Post  
Brian White
 
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Default

And for your next question, no, you do not have to use 20A rated
outlets on a 20 Amp circuit - the 15 Amp duplex outlets are fine.


Check your local building code. Up here in Ontario, you _must_ use 20A
rated outlets if you have a 20A breaker.

Hmmm... Hold on... I've said that a few times but now that I think about
it, the part of the code I'm thinking was dealing with a kitchen countertop
where you ether had to have a split-circuit recepticle or a single 20A
circuit (complete with 20A outlet). It's possible that it's not required
to have a 20A outlet on a 20A circuit in other situations. But why take
the chance? It doesn't make good sense to use a 15A rated part in one
place when the your only piece of protection (the breaker) is rated at
20A. Plus, if you ever had a 20A piece of equipment, at least you'd
have a recepticle that would take it.

Brian
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DaveG
 
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Default


"Brian White" wrote in message
...
And for your next question, no, you do not have to use 20A rated
outlets on a 20 Amp circuit - the 15 Amp duplex outlets are fine.


Check your local building code. Up here in Ontario, you _must_ use 20A
rated outlets if you have a 20A breaker.


Maybe so in Canada, but in the USA we are certainly allowed to install 15
amp outlets on 20 amp circuits. In fact, you can install as many on a
circuit as you wish. Homebuilders do it all the time.
In fact, we get our electrical jollies doing it.


Hmmm... Hold on... I've said that a few times but now that I think about
it, the part of the code I'm thinking was dealing with a kitchen
countertop
where you ether had to have a split-circuit recepticle or a single 20A
circuit (complete with 20A outlet).


Again, maybe in Canada, not in USA. There are 20 amp wiring requirements
for kitchens, but no requirement for a 20 amp outlet. Last time I checked,
my toaster, blender, coffe maker, electric skillet, and anything else I am
likely to plug in my kitchen doesn't have the kind of plug that requires a
20 amp outlet.


It's possible that it's not required
to have a 20A outlet on a 20A circuit in other situations.


In mainstream house wiring it's really not required anywhere, with the
possible exception for a dedicated circuit for something like an air
compressor or other high draw device. Again, that's NEC.
Things up there may be different.


But why take the chance?

What chance? There is absolutely NO DANGER IN PUTTING 15 AMP OUTLETS ON 20
AMP WIRING. NONE, NADA, ZILCH. Keep in mind that a 15 amp outlet won't
allow anything to be plugged into it that will draw over 15 amps. For that
very reason, it is not allowed to put a 20 amp outlet on a 15 amp circuit.
This is where you could potentially plug something in that would over draw
the wiring.


It doesn't make good sense to use a 15A rated part in one place when the
your only piece of protection (the breaker) is rated at 20A.


You clearly don't understand the concept. Let me repeat myself. A 15 amp
outlet will not allow anything to be plugged into it that would allow the
wiring, outlet, and breaker. Power is drawn from the load, not pushed from
the supply. A 15 amp outlet is fine on a 20 amp circuit. The outlet wont
melt, explode, or anything, because nothing that will draw too much current
will be plugged into it.
Get it yet?


Plus, if you ever had a 20A piece of equipment, at least you'd have a
recepticle that would take it.

Please take inventory of everything you own, and list what you have that has
the special plug configuration that requires a 20 amp outlet. I'm not even
sure what type of appliance, tool, or widget this would be.


By the way, your other post was really amusing. Where did you get that 240
amp kitchen code requirement?

Brian

I don't know about the Canadian electrical code, but here in the USA, it's
And you'd be taking ABSOLUTELY NO CHANCES by doing this. All you'd be doing
is what home builders do all over the place. I'm not even sure what kind of
appliance even has the plug configuration that requires a 20 amp outlet.
What makes no sense is spending a pile of money on 20 amp outlets when you
don't need them.




  #6   Report Post  
Brian White
 
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Default

And for your next question, no, you do not have to use 20A rated
outlets on a 20 Amp circuit - the 15 Amp duplex outlets are fine.


Check your local building code. Up here in Ontario, you _must_ use 20A
rated outlets if you have a 20A breaker.


Maybe so in Canada, but in the USA we are certainly allowed to install 15
amp outlets on 20 amp circuits. In fact, you can install as many on a
circuit as you wish. Homebuilders do it all the time.
In fact, we get our electrical jollies doing it.


As somebody pointed out, even "15A" recepticles are rated for 20A feed-
through. That's what is important. They're not not configured/rated
for 20A appliances.


Hmmm... Hold on... I've said that a few times but now that I think about
it, the part of the code I'm thinking was dealing with a kitchen
countertop
where you ether had to have a split-circuit recepticle or a single 20A
circuit (complete with 20A outlet).


Again, maybe in Canada, not in USA. There are 20 amp wiring requirements
for kitchens, but no requirement for a 20 amp outlet. Last time I checked,
my toaster, blender, coffe maker, electric skillet, and anything else I am
likely to plug in my kitchen doesn't have the kind of plug that requires a
20 amp outlet.


I know. I didn't understand why a 20A outlet was necessary either, but
it's "code" and if I wanted to pass my inspection...


In mainstream house wiring it's really not required anywhere, with the
possible exception for a dedicated circuit for something like an air
compressor or other high draw device. Again, that's NEC.
Things up there may be different.


And those devices should have 20A plugs if they're going to draw a 20A
surge.


But why take the chance?

What chance? There is absolutely NO DANGER IN PUTTING 15 AMP OUTLETS ON 20
AMP WIRING. NONE, NADA, ZILCH. Keep in mind that a 15 amp outlet won't
allow anything to be plugged into it that will draw over 15 amps. For that
very reason, it is not allowed to put a 20 amp outlet on a 15 amp circuit.
This is where you could potentially plug something in that would over draw
the wiring.


Yes, there IS A DANGER _if_ at outlet were only rated for 15A. However,
since a 15A outlet is still rated to handle 20A of current (though not to a single device), then you're still okay.

We're in violent agreement here. grin


It doesn't make good sense to use a 15A rated part in one place when the
your only piece of protection (the breaker) is rated at 20A.

You clearly don't understand the concept. Let me repeat myself. A 15 amp
outlet will not allow anything to be plugged into it that would allow the
wiring, outlet, and breaker. Power is drawn from the load, not pushed from
the supply. A 15 amp outlet is fine on a 20 amp circuit. The outlet wont
melt, explode, or anything, because nothing that will draw too much current
will be plugged into it.


Note that what you say here is technically wrong. NO simple outlet
protects against things being plugged in to it. I could easily add
a power bar or string Christmas lights together and try to draw more
than 15A from a single socket. It may make things more difficult
(for example not allowing a 20A plug to fit) but _all_ protection
comes from the CB in the panel, not the outlet (at least, not a
standard simple one).

But, since a 15A outlet is actually rated for 20A current it's fine to
use on a 20A circuit. I did not know this when I made my original post.


Get it yet?


I do. Do you?


Plus, if you ever had a 20A piece of equipment, at least you'd have a
recepticle that would take it.

Please take inventory of everything you own, and list what you have that has
the special plug configuration that requires a 20 amp outlet. I'm not even
sure what type of appliance, tool, or widget this would be.


Mostly shop equipment; a lathe for example might require 20A.


By the way, your other post was really amusing. Where did you get that 240
amp kitchen code requirement?


- every appliance has to have it's own 15A circuit:
dishwasher, garbage disposal, fridge, microwave 60A
- countertop: split circuit or 20A, every 6 feet, adjacent must
be on different circuits, next to sink must be GFI:
1 x 15A@240V-split, 2 x 20A (GFI outlets) 70A @ 120V
- stove/oven: 40A (required present even if using gas)
oven doesn't draw that much, cooktop is gas 40A @ 240V
- lights: must be on separate circuit
one circuit for all lights 15A
- smoke / explosive gas detector
separate circuit if running 3-wire "ring all" config 15A
============
240A @ 120V

The panel in the basement is 100A @ 240V. You can see the history of
the renovation he http://pobox.com/~bcwhite/beaumaris/kitchen/ It
_is_ actually finished now... I just haven't finished the write-up.

Brian
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  #7   Report Post  
Playintennis5274
 
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same gauge may have quite different specs as far as resistance. The type of
configuration, flexibility, flex fatigue, and the cover also make a
difference.


how does the cover make a differance?
  #8   Report Post  
Brian White
 
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Power is drawn from the load, not pushed from the supply.

It occurred to me later that this is incorrect. Power _is_ pushed from
the supply (with a force of approximately 120V). It's how well the load
resists this push that determines how much current it will pass. Open
air resists it very well; copper wire does not.

Voltage is a potential energy, much like (to use a frequent analogy) a
lake at the top of a waterfall. As it falls, the potential is converted
to heat, motion, whatever by the mechanisim through which the current
passes.

Brian
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