AVS Forum banner
Status
Not open for further replies.
1 - 9 of 9 Posts

·
Registered
Joined
·
832 Posts
Discussion Starter · #1 ·
A lot of the lighting in my house is serviced by 14gauge wire, but are fed by 20amp breakers, is this a potential problem? I also have a lot of 15 amp outlets fed by 12 gauge wire and 20 amp breakers, is this a problem?


Since most residential outlets (certainly the typical ones you see at home depot and the like) are 15 amp rated, does that mean most residential breakers should be 15 amps, and the house should be wired with 14gauge wire (everything else is overkill)?


Eric.
 

·
Registered
Joined
·
1,726 Posts
I ran into a similar problem last night. Lots of people here recommended 20a outlets for my equipment rack, but when I went to Home Depot they only had 15A outlets for my equipment. The 20A oultets had a different prong with one of them going sideways, like this:


--- |


|


My equipment won't plug into that.
 

·
Registered
Joined
·
832 Posts
Discussion Starter · #3 ·
I know you can get 20amp ones that fit both. The hot and neutral look like this: -| |
 

·
Registered
Joined
·
268 Posts
Larry may disagree with me here but I always use 20 amp rated outlets on a 20 amp circuit. (20 amp breaker at the box and 12 wire). It is not good to o use a 20 amp breaker with a 14 wire run ever. It is fine to have a 15 amp breaker ahead of a 12 gauge wire run. That is standard today.
 

·
Registered
Joined
·
832 Posts
Discussion Starter · #5 ·
I have good news! I just checked, and it looks like theres really only one circuit that is out of spec. I should be able to pickup a 15 amp breaker for the one lighting circuit fed by 14gauge wire.
 

·
Registered
Joined
·
3,947 Posts
First of all, breakers (and fuses - remember fuses?) are there to protect the wire, period. they don't care about the appliance or other loads connected to them, except when they are selected for a single specific load, such as motor over-current protection. When wire is overloaded, it overheats, and the insulation is damaged, which results in fire risks.


So, yes, there is a danger having 14-gauge wire on a 20-amp breaker. The opposite is never a problem; 12 gauge wire on a 15-amp breaker is not a risk, except for possible nuisance tripping. The wire determines the circuit capacity and the required breaker size. 14 ga. wire needs a 15 amp breaker (max), 12 ga. needs a 20 (max), and 10 ga. needs a 30 (max).


It never hurts to use a wire larger than required, especially for long runs to reduce voltage drop, which is current-dependent, but otherwise, it can be a waste of money and make connecting the wiring to the devcices, as well as stuffing it all into the boxes, more difficult.


About the receptacles: The 15-amp receptacles on 20-amp circuits (and 12 ga. wire) is perfectly okay. 15-amp and 20-amp receptacles are internally identical; the only difference is the slot shape, and code allows 15-amp receptacles on either 15- or 20-amp circuits, with one exception: a single receptacle (not one duplex, but one single-plug outlet) is required to match its circuit rating.


By the way, every 20-amp,120-volt receptacle I've seen has a T-shaped neutral slot, meaning that either 15- or 20-amp plugs will fit. The idea is that equipment that requires a 20-amp circuit won't be plugged into a circuit that can't handle it, but a smaller load can be used on either-rated circuit.


As an aside, the same is true of 240-volt receptacles: a 20-amp,240-volt receptacle will accept either a 15- or 20-amp plug. It's just that the right slot is horizontal. The whole idea is rejection of an unsafe combination. Here are the NEMA configurations:


120-volt, 15-amp: | . |


120-volt, 20 amp: – . |


240-volt, 15 amp: – . –


240-volt, 20-amp: | . –


Actually, NEMA configurations show the receptacles rotated, with the ground pin at the top, which retains the plug more firmly, but most residential installations have it the way I showed above. I guess it's because it's more asthetically pleasing to see the 'happy face'.
 

·
Registered
Joined
·
268 Posts
The reason I install 20 amp outlets on a circuit that has a 20 amp breaker is so that it is readily identifiable as 20 amp capable. There are appliances and tools that should only be used on a 20 amp run. I have a wallpaper steamer that clearly states " requires 18 amps". It has a normal three prong plug but will pop a 15 amp breaker every single time it is used on a 15 amp run.
 

·
Registered
Joined
·
3,947 Posts
Wayne, I dig. That's a common problem; my table saw doesn't like 15-amp circuits, either. Technically, the steamer draws even more than a 20-amp circuit should have on it. 80% of 20 is 16.
 

·
Registered
Joined
·
1,726 Posts
Maybe it is a different code in Canada. Both my electrician and retail electrical people at Home Depot and another large Canadian retailer (Rona) here in Canada stated that you cannot buy a 20A receptacle that will fit a typical appliance, you need a 20A plug. My electrician also told me that it is against code to run a 20A circuit to a 15A outlet in Canada. I guess I will have to settle for 15A...
 
1 - 9 of 9 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Status
Not open for further replies.
Top