Single receptacle question

[LarryFine]

I use the 20 a rec when replacing a burned rec where floor heaters, irons, fry pans etc have been used . The 15 amp cord fits much tighter and the rec wont burn as easily

The conductive parts of equal-quality 15a and 20a receptadcles are the same.

That's one of the reasons 15a receptacles are permitted on 20a circuits.

 

[iwire]

I use the 20 a rec when replacing a burned rec where floor heaters, irons, fry pans etc have been used . The 15 amp cord fits much tighter and the rec wont burn as easily

OK first thing to relize is that the internal parts of the same grade and manufacturer receptacle are identical for 15 and 20 amp duplex receptacles.


Why?

For one thing they have to meet UL listing requirements to be able to handle 20 amp feed through.

For another economics of production, there would be little if any cost savings from making two different sets of internal parts with only 5 amps difference in rating.

ON this post I was refering to installing 20 a rec on a 20 circuit. No matter what code says I dont believe a 20a rec should be installed 15 a circuit. The reason is a 15a circuit should only be loaded to 12 a and a 20 a cord could be used to draw 15a and not trip the breaker.

So are we to assume you use only single receptacles with home runs to the panel for each?

A single 15 amp duplex can easily have two 12 amp heaters plugged into it.

Ok, my idea of simplifying this section of the code was shot down. But let me ask this question. Why do we allow 15 amp receptacles to be installed on 20 amp circuits?

A better questions is why shouldent we?

What is the safety issue?

We will allow ten 15 amp duplex receptacles on a single 15 amp circuit.

Because 15 amp receptacles are cheaper?

Spec grade 15s cost more then bargain 20s.

Why not just require 15 amp receptacles for 15 amp circuits? 20 amp receptacles for 20 amp circuits etc. ? With this system one could tell by looking at the receptacle what the amperage of the circuit would be.

Yet we would still have no idea how much load has already been put on the circuit.

Basically the system we have is working fine and presents no safety issue.

 

[Greg1707]

"OK first thing to realize is that the internal parts of the same grade and manufacturer receptacle are identical for 15 and 20 amp duplex receptacles."


Why are 20 amp receptacles more expensive?:-?

 

[LarryFine]

Why are 20 amp receptacles more expensive?:-?

Supply and demand.

Are you sure you're comparing equal-grade receptacles?

 

[wawireguy]

Is a duplex receptacle one or two receptacles? I'd say it is two, so I can put one duplex 15 amp receptacle on a dedicated 20 amp circuit without violating code.

 

[480sparky]

.............Why are 20 amp receptacles more expensive?:-?

Same reason 24" fluorescent lamps cost more than 48" ones......... they sell more of 'em.

 

[480sparky]

Is a duplex receptacle one or two receptacles? I'd say it is two, so I can put one duplex 15 amp receptacle on a dedicated 20 amp circuit without violating code.

Duplex means two.

 

[M. D.]

Seeing how an individual branch circuit supplies only one utilization equipment it really is no big mystery as to the receptacle required for such equipment .. Yes I guess you could have a situation where a piece of equipment with a 10 amp draw has a 50 amp attachment plug ,. but I doubt it .. the closest thing to that would be Rob's example of the range receptacle outlet with a 40 amp ocpd and 50 amp receptacle outlet.

 

[hurk27]

Is a duplex receptacle one or two receptacles? I'd say it is two, so I can put one duplex 15 amp receptacle on a dedicated 20 amp circuit without violating code.

And the code would agree with you:

Receptacle. A receptacle is a contact device installed at the outlet for the connection of an attachment plug. A single receptacle is a single contact device with no other contact device on the same yoke. A multiple receptacle is two or more contact devices on the same yoke.

But I know 210.21 doesn't stop you from using a single 20 amp receptacle on a 15 amp circuit, but table 210.21(B)(3) clearly does not allow a 20 amp duplex on a 15 amp circuit, it says for a 15 amp circuit a receptacle "Not Over 15 amps"

Now to confuse this more, is 210.23:

210.23 Permissible Loads.
In no case shall the load exceed the branch-circuit ampere rating.

and a single 20 amp receptacle on a 15 amp circuit would allow this to happen??

 

[M. D.]

see that's just what I mean an IBC supplies one piece of utlization equipment not receptacles

 

[LarryFine]

... and a single 20 amp receptacle on a 15 amp circuit would allow this to happen??

The 20a receptacle suggests to the user that the circuit is 20a-capable.