To many amps?

[Kentuckian]

This may come as a common sense question to some but here goes. A lady has a duplex gfci receptacle on a 120v circuit with 20A breaker. Coming from each receptacle is a power strip rated for 12A. She has 2 different things that are going to be plugged in but there's 5 of each for a total of 10. all together will pull 22.5A. I know your not supposed to put over 80% load on a breaker right? I'm also thinking the gfci would keep tripping or the power strip itself would keep tripping. Would i need to wire up another circuit? Thanks


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[luckylerado]

The breaker will trip. I do not think that the GFI or either of the strips will trip. Probably a 15 amp device too??

 

[mbrooke]

A breaker can handle 100% current without tripping. Where did you get the 80% number from?

 

[just the cowboy]

Nothing may trip

Nothing may trip

From what you said nothing may trip. Due to the trip curves and tolarances on a breaker 10% over may not trip anything. BUT that is the reason that you should run another circuit it WILL be heating something up that may cause a failure.

 

[Kentuckian]

1 device is 1.5 amps the other is 3 amps. But there will be 5 of each


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[Kentuckian]

A breaker can handle 100% current without tripping. Where did you get the 80% number from?

I know it can handle 100% but I was thinking code recommended to only load it with 80%


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[zbang]

1 device is 1.5 amps the other is 3 amps. But there will be 5 of each

Is that the rated load or the actual measured load? Quite often small devices draw substantially less than the plate on the side says. Or... sometimes the wattage shown is correct but the amps are high ("100 watts, 2 amps"; that sort of thing).

 

[JFletcher]

A breaker can handle 100% current without tripping. Where did you get the 80% number from?

He may be figuring continuous loads. Kentuckian, is this for holiday lighting? Also, there is probably other loads on that circuit.

 

[Kentuckian]

Not for holiday lighting. I work in a hospital and we was adding some equipment. I'm pretty sure there isn't anything on the circuit but I will make sure before I make any connect anything.


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[Kentuckian]

Is that the rated load or the actual measured load? Quite often small devices draw substantially less than the plate on the side says. Or... sometimes the wattage shown is correct but the amps are high ("100 watts, 2 amps"; that sort of thing).

It was the rated load


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[Barbqranch]

Will they all be on at the same time, and if so, for how long?

 

[mbrooke]

He may be figuring continuous loads. Kentuckian, is this for holiday lighting? Also, there is probably other loads on that circuit.

He might, but for a resi I wouldn't worry about it unless its 100% known or written in code.

 

[GoldDigger]

I know it can handle 100% but I was thinking code recommended to only load it with 80%


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That is not quite how it goes, but close.
The code does not recommend anything. It requires some things and allows other things at your choice. And whatever is not prohibited is allowed.

When figuring out circuit loading (branch, feeder, service), continuous non-motor loads are calculated at 125% of rated to get the load figure.
Specifically for circuit breakers, the calculated load (used to size the wires) shall not be more than 80% of the rating of a standard circuit breaker in a standard panel.

 

[ADub]

If these devices aren't going to be running at the same time all the time then there is probably no issue.


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[Dennis Alwon]

Why would you load a 20 amp circuit over 20 amps. Do the job the correct way and get another circuit there. Plug strips??? I hope this isn't in patient care areas.

 

[J.P.]

1 device is 1.5 amps the other is 3 amps. But there will be 5 of each.

With only that info..... 5x1.5 and 5x3

7.5 amps and 15 amps. You need two circuits if they are continuous or likely to run at the same time.

A breaker would probably hold that 22.5 amp load no problem though as long as it wasn't starting a motor or something.

 

[iwire]

Why would you load a 20 amp circuit over 20 amps. Do the job the correct way and get another circuit there. Plug strips??? I hope this isn't in patient care areas.

First commonsense answer in this thread.

 

[Smart $]

I know it can handle 100% but I was thinking code recommended to only load it with 80%...

Only requirement similar in nature is 210.23(A)(1), which limits any one portable cord-and-plug-connected equipment to 80%. Not the case here.

 

[FionaZuppa]

That is not quite how it goes, but close.
The code does not recommend anything. It requires some things and allows other things at your choice. And whatever is not prohibited is allowed.

When figuring out circuit loading (branch, feeder, service), continuous non-motor loads are calculated at 125% of rated to get the load figure.
Specifically for circuit breakers, the calculated load (used to size the wires) shall not be more than 80% of the rating of a standard circuit breaker in a standard panel.

well, its 125% continuous + 100% non-continuous. certainly using just 125% is ok.

whats not so clear to me is where diversity comes in. say four 15A single outlets on a bc w/ 15A ocpd. the bc has possibility to be loaded to 60A, so is the calc'd load now 48A?

 

[iwire]

whats not so clear to me is where diversity comes in. say four 15A single outlets on a bc w/ 15A ocpd. the bc has possibility to be loaded to 60A, so is the calc'd load now 48A?

Read article 220.