How Hi FLA on a 20A breaker

[fifty60]

I have some equipment that will hopefully become UL listed. Will UL hold me to the 80% of the CB rule when it comes to equipment that is powered from a standard 20A wall outlet? I am currently at 17.5A, calculated worst case.

Is there anything in NFPA 70 that covers this?

 

[jumper]

If your load is non continuous the breaker can be loaded to 100%.

210.20(A) Continuous and Noncontinuous Loads. Where a
branch circuit supplies continuous loads or any combination
of continuous and noncontinuous loads, the rating of
the overcurrent device shall not be less than the noncontinuous
load plus 125 percent of the continuous load.

 

[suemarkp]

I wonder if they will require a "this must be connected to an individual branch circuit of 20A" in your instructions. A given cord connected appliance on a multi-outlet branch circuit is limited to 80% of the circuit rating. See NEC 210.21(B)(2) and table 210.21(B)(2).

 

[Smart $]

I wonder if they will require a "this must be connected to an individual branch circuit of 20A" in your instructions. A given cord connected appliance on a multi-outlet branch circuit is limited to 80% of the circuit rating. See NEC 210.21(B)(2) and table 210.21(B)(2).

That's maximum cord-and-plug-connected load... for all equipment on circuit.

Cord-and-plug-connected equipment not fastened in place [210.23(A)(1)] is also limited to 80%.

However, cord-and-plug-connected, fastened-in-place equipment is limited to 50% of the circuit rating where other equipment is also supplied by the circuit [210.23(A)(2)]. Detail in this regard has not been provided. Considering the various possibilities, its still pretty much limited to an individual branch circuit... but there is just a tad of wiggle room there.

 

[suemarkp]

I agree your 210.23(A)(1) is the more accurate code section. But I think it seems to be repeating 210.21(B)(2) which says:
Total Cord-and-Plug-Connected Load. Where connected to a branch circuit supplying two or more receptacles or outlets, a receptacle shall not supply a total cord-and-plug-connected load in excess of the maximum specified in Table 210.21(B)(2).

Receptacle is singular, not plural. But the "Total cord-and-plug connected load" is misleading. I know of no provision disallowing a circuit to be loaded to 100% of rating as long as the items are not continuous and no one item is larger than 80% of the circuit rating. Also quite difficult to enforce.

 

[Smart $]

I agree your 210.23(A)(1) is the more accurate code section. But I think it seems to be repeating 210.21(B)(2) which says:
Total Cord-and-Plug-Connected Load. Where connected to a branch circuit supplying two or more receptacles or outlets, a receptacle shall not supply a total cord-and-plug-connected load in excess of the maximum specified in Table 210.21(B)(2).

Receptacle is singular, not plural. But the "Total cord-and-plug connected load" is misleading. I know of no provision disallowing a circuit to be loaded to 100% of rating as long as the items are not continuous and no one item is larger than 80% of the circuit rating. Also quite difficult to enforce.

You are correct. Its total load on one receptacle... but can include more than one load, such as several connected via power strip.

210.23(A) is the limitation for any one load, no matter how it is connected.


I disagree with your ending comment only in the sense that it is not just difficult to enforce, it is impossible to enforce.

 

[infinity]

What about a 20 amp circuit with a single receptacle and a 17.5 amp, non-continuous load as mentioned in the OP?

 

[jumper]

What about a 20 amp circuit with a single receptacle and a 17.5 amp, non-continuous load as mentioned in the OP?

Should be legal AFAICT.

 

[jumper]

Should be legal AFAICT.

I just noticed that OP said "standard 20A wall outlet", that is gonna have to be a single and not a duplex to work as Rob put it.