Electrical outlet question

ked said:

It is not OK to install a 20 amp receptacle on a 15 amp circuit. Look at the table above. It makes the user think that there is a 20 amp circuit feeding the receptacle. Same reason you do not put a 50 amp receptacle on a 30 amp circuit. Our local inspectors require a 20 amp duplex ( or single ) where a 20 amp circuit serves only one outlet.

Click to expand...

We were talking about single receptacles, your referring to duplex receptacles,
It is legal to install a 20a single round receptacle on a dedicated 15amp circuit.
take a look at 210.21 (B)(1)

What code section would prohibit you from installing a 50 amp single receptacle on a 30 amp individual branch circuit?

Table 210.21 B 3 , Receptacle Ratings: 15 amp circuit rating = Not over 15 amps (not 20!)
same table: 30 amp rating = 30 amps (not 50!)
The 50 amp receptacle is allowed on a 40 amp circuit because some ranges need only a 40 amp circuit and the 50 amp receptacle and plug is safe and convenient to use....
There are many and varied of interpretations of the Code. By "Local Inspector," I mean the head of the local building department. The AHJ can modify the Code and as long as it is in writing, I go with it. In Petaluma, CA, smoke detectors and paddle fans are excluded from AFCI protection-good idea. At one time they outlawed all Aluminum wiring-good idea, but it proved too expensive. In many cities, NM-Romex is outlawed. In SF, every wire must have its own drilled or punched hole.... May I suggest that you do not tell the AHJ, usually backed with a staff with hundreds of years of combined experience, that they are wrong. Possibly mistaken, please reconsider, perhaps, but not wrong.

ked said:

Table 210.21 B 3 , Receptacle Ratings: 15 amp circuit rating = Not over 15 amps (not 20!)
same table: 30 amp rating = 30 amps (not 50!)
The 50 amp receptacle is allowed on a 40 amp circuit because some ranges need only a 40 amp circuit and the 50 amp receptacle and plug is safe and convenient to use....
... May I suggest that you do not tell the AHJ, usually backed with a staff with hundreds of years of combined experience, that they are wrong. Possibly mistaken, please reconsider, perhaps, but not wrong.

Click to expand...

All of the code must be considered.

210.21(B)(1) applies to a SINGLE receptacle on a branch circuit, and says that the receptacle shall have an ampere rating not less than that of the branch circuit, but does not prohibit a receptacle with a rating larger than the rating of the branch circuit..

210.21(B)(3) applies to a branh circuit supplying TWO OR MORE receptacles or outlets and requires that receptacles on 15 ampere branch circuits not be GREATER THAN 15 ampere rating, and that receptacles on 20 ampere branch circuits may be 15 or 20 ampere rating.

ground

I believe putting the ground opening on the top started in hospitals so that dropping, or inserting, any flat metal object onto a partially inserted plug would short out before the user could be shocked.

hj said:

I believe putting the ground opening on the top started in hospitals so that dropping, or inserting, any flat metal object onto a partially inserted plug would short out before the user could be shocked.

Click to expand...

I was in an exam room in the new emergency wing of a large hospital this week. There were 7 duplex receptacles, some red and some white. Every one of them had the ground plug DOWN.

ked said:

Table 210.21 B 3 , Receptacle Ratings: 15 amp circuit rating = Not over 15 amps (not 20!)
same table: 30 amp rating = 30 amps (not 50!)
The 50 amp receptacle is allowed on a 40 amp circuit because some ranges need only a 40 amp circuit and the 50 amp receptacle and plug is safe and convenient to use....

Click to expand...

You can't just say a 40 is safe on a 50 that is just silly, it's allowed for a reason, you just didn't actually read the code book...

and that table you mentioned is NOT for single receptacles. Try actually reading 210.21(B)(1)

Table 210.21 B 3 is for a circuit with two or more outlets. Note that you cannot put receptacles rated MORE than 15,20, 30, 50 on circuits with respectively, 15,20, 30, 50 amp ratings. The 40 amp circuit can have two or more 50 amp receptacles installed at its outlets.
The issue is about single receptacles.... If you read "the letter" of the Code it will allow you to put a 50 amp receptacle on a 15 amp circuit. I am saying that our local inspectors will make you tear it out and match the circuit with the receptacle. 15=15, 20=20, 30=30, 50=50. The logic is that joe schmo homeowner sees a 30 amp receptacle and thinks that he can plug a dryer into it--but it is fed by only 15 amps?? It is assumed that the Code panel assumed that electricians will not want to install a more expensive receptacle. Also our local inspector is convinced that "single receptacle" means "single outlet," so you can plug the washer AND dryer into that single 20 amp duplex outlet. The Code panels are only human--that is why AHJs are allowed to modify the Code to arrive at local code rules.

ked said:

The logic is that joe schmo homeowner sees a 30 amp receptacle and thinks that he can plug a dryer into it--but it is fed by only 15 amps?? .

Click to expand...

And what would be the problem? Other than poor design?

ked said:

It is assumed that the Code panel assumed that electricians will not want to install a more expensive receptacle.

Click to expand...

I disagree.

ked said:

Also our local inspector is convinced that "single receptacle" means "single outlet," so you can plug the washer AND dryer into that single 20 amp duplex outlet.

Click to expand...

How can you plug two devices into a single receptacle? Your inspector is not educated.

ked said:

The Code panels are only human--that is why AHJs are allowed to modify the Code to arrive at local code rules.

Click to expand...

Your only agreeing to dumb down the electrical code for non electricians...

ked said:

Also our local inspector is convinced that "single receptacle" means "single outlet,"... The Code panels are only human--that is why AHJs are allowed to modify the Code to arrive at local code rules.

Click to expand...

Sounds like your inspector is more human than the code panels.

It is not just one inspector, it is the whole building department.
The problem with a 30 amp receptacle on a 15 amp circuit is that the customer will blow the 15 amp circuit breaker and perhaps "upgrade" to a 30 amp breaker!!

ked said:

It is not just one inspector, it is the whole building department.
The problem with a 30 amp receptacle on a 15 amp circuit is that the customer will blow the 15 amp circuit breaker

Click to expand...

Not a code violation. sounds like a bad design issue.

ked said:

and perhaps "upgrade" to a 30 amp breaker!!

Click to expand...

Could happen under any circumstance... its called untrained and unqualified.



Since when do we worry about the what if's, also what about a 40 amp breaker on a 50 amp range receptacle? if this is not allowed than your building department has some real issues, and if the DO allow it then they must allow a 15amp circuit on a 30 amp receptacle... also, if your state does NOT have a amendment on this issue then your local inspectors are playing hero again...

ked said:

In SF, every wire must have its own drilled or punched hole....

Click to expand...

You CANNOT be serious!


Ked, you need to worry more about the actual code than just blindly doing what the inspector says, just because he is the inspector.

Contrary to what you think, AHJs are NOT allowed to simply "modify" the code as they see fit.