20 Amp outlets

[Teken]

I had the chance to see the insides of a 20 amp outlet the other day and compared it to a standard 15 amp outlet.

Using a caliper, ruler, and magnifying glass I honestly couldn't tell how the extra 5 amps is accomplished?

The only thing off the top of my head is that the basic designs contact terminals are over rated to at least sustain 15-20 amps for prolonged durations.

Now, this doesn't address the cable supplying the fixture that is a given since you would be using 12-2, 12-3 romex wire to carry the current to the end device. Same with a 15 amp fixture (here in the 51st state) 14-2, 14-3 is standard code.

Besides the obvious cross slit on the 20 amp outlet I really couldn't see any physical difference to a standard 15 amp outlet.

Insight . . .

 

[ishiboo]

I had the chance to see the insides of a 20 amp outlet the other day and compared it to a standard 15 amp outlet.

Using a caliper, ruler, and magnifying glass I honestly couldn't tell how the extra 5 amps is accomplished?

The only thing off the top of my head is that the basic designs contact terminals are over rated to at least sustain 15-20 amps for prolonged durations.

Now, this doesn't address the cable supplying the fixture that is a given since you would be using 12-2, 12-3 romex wire to carry the current to the end device. Same with a 15 amp fixture (here in the 51st state) 14-2, 14-3 is standard code.

Besides the obvious cross slit on the 20 amp outlet I really couldn't see any physical difference to a standard 15 amp outlet.

Insight . . .

It's more of a matter of the physical interlock of not being able to plug a 20A plug into a 15A receptacle, than it is the actual capability of safely carrying the extra five amps.

The 20A recaps I buy are typically higher quality than the cheap-o 15A's, and often have the nice "back wire" option where the wires are held by screw clamps.

 

[Teken]

I swear I thought I read a thread here a few years ago explaining that there was a difference.

The only part I wouldn't be able to confirm is the body of the casing as some devices have a higher melting point etc.

I agree besides the physical side slit on the out let I don't know if there is a load carrying difference in these outlets.

 

[ishiboo]

I swear I thought I read a thread here a few years ago explaining that there was a difference.

The only part I wouldn't be able to confirm is the body of the casing as some devices have a higher melting point etc.

I agree besides the physical side slit on the out let I don't know if there is a load carrying difference in these outlets.

Well, the contacts may be better protected against arc wear, grip the plug better, etc... differences are small but I'm sure they're there. 15A outlets vary quite a bit in quality though it may hard for you to measure Would also vary between brands/price points.

What's the reason for sitting down with a caliper, ruler and magnifying glass? If I had that kind of free time I'm sure I could find better things to spend it on

 

[travisd]

Given that it's legal to have (multiple) 15A outlets on a 20A circuit, they better be able to pass 20A...

 

[malibu101]

Pretty much how 30-60 amp plugs and outlets are the same too.
Other than the pin configuration, they have the same size contacts and basic construction.
Look at your average 30A dryer outlet then look at you average 50A range outlet side by side. Other than configuration they are virtually the same.
And what travisd said too.

 

[Teken]

Given that it's legal to have (multiple) 15A outlets on a 20A circuit, they better be able to pass 20A...

Pretty much how 30-60 amp plugs and outlets are the same too.
Other than the pin configuration, they have the same size contacts and basic construction.
Look at your average 30A dryer outlet then look at you average 50A range outlet side by side. Other than configuration they are virtually the same.
And what travisd said too.

See that is what I mean . . . But, keep in mind the NEC for you guys states all wiring in the house must be a minimum of 12-2, 12-3 that already gives you the 20 ampacity to carry that amount of current.

Here in the North they haven't gotten through their heads that 12-2, 12-3 wire should be the minimum wire guage used.

I plan on wiring my entire basement using 12-2, 12-3 romex in the future.

 

[Teken]

What's the reason for sitting down with a caliper, ruler and magnifying glass? If I had that kind of free time I'm sure I could find better things to spend it on

One of the guys was killing time and decided to cut a few old outlets in half to see how they were made.

I figured what the hay . . .

Can't honestly say I have ever taken the time to see the insides of a outlet / switch before so I thought this would be a good time to do some measurements and see if there was any difference(s) . . .

Yes, we were bored and had nothing to do . . .

 

[Stuart in MN]

As far as I know, all 15 amp duplex receptacles sold new in the US are rated for 20 amp feedthrough. If you're in Canada I can't vouch for what they sell there but I suspect they are the same thing. As a result, the only real difference between a 15 amp and a 20 amp receptacle will be the configuration of the socket - a 20 amp receptacle has a T shaped socket on the neutral side.

The NEC says you have to use #12 wire for 20 amp circuits, but #14 is okay for 15 amp circuits.

Very few household devices or workshop tools come with 20 amp plugs on them, so in most cases using 15 amp receptacles is fine.

The quality of the contacts, the plastic body, etc. is more of a function of how much you're paying than anything else. The receptacles in the 29 cent bin at the big box store aren't built to the same standards as the ones you pay several dollars for.

 

[Charles (in GA)]

If you compare "apples" with "apples" such as the Leviton 15 amp Prograde side and backwire model 5252 at $5.44 with the Leviton 5352 at $6.49 which is the same Prograde side and back wired receptacle (though not identified as such on the web site) with a flat nylon face, exact same units except for the horizontal slot on it......... if you peer thru the slots, or break them open, you will find on the 15 amp, the same contacts inside, even the horizontal one, not one difference except for the face plate.

You can do this with Cooper, or Hubbell, or which ever is your favorite brand, and find that, while you are spending a dollar more for the 20 amp version, you are getting NOTHING extra, other than the rating.

Charles

 

[Teken]

This is what I gathered upon first inspection. Mind you even though this was purely a visual and off the cuff measurement I could see that none of the internals were any thicker, longer, or used different metals to increase the current rating.

As I said earlier it wasn't possible to confirm that the dielectric insulation / housing was any stronger than the 15 amp model.

Just for **** and giggles we did send it out to be tested to see what the casing could with stand in terms of line voltage.

The package does state what it is, but they decided to just see if it was under rated or at spec.

I am guessing it will come back under rated . . .

 

[mrb]

think about it from a manufacturing standpoint. are you going to have complete seperate sets of tooling for two different models that are the same save for one slot? Or do you use one set of tooling for everything and have a different mold for the face only?

the plastic is exactly the same. the ONLY thing different is the slot, and that is to keep one from plugging a device that requires a 20 amp circuit into a 15 amp circuit.