Heater

[hhsting]

You guys sure do close threads fast. Below thread if the instant water heater is considered non continuous how can factor of more than 100% apply to that load let alone 422.11(E)(3) which says 150%?

Instantenous water heater

I have 4.1kw, 277V single phase instantaneous water heater full load amps of 14.8A. The breaker provided is 20A. Since instant water heater is non continuous load should not the breaker be sized 15A?

forums.mikeholt.com

 

[david luchini]

You guys sure do close threads fast. Below thread if the instant water heater is considered non continuous how can factor of more than 100% apply to that load let alone 422.11(E)(3) which says 150%?

Instantenous water heater

I have 4.1kw, 277V single phase instantaneous water heater full load amps of 14.8A. The breaker provided is 20A. Since instant water heater is non continuous load should not the breaker be sized 15A?

forums.mikeholt.com

422.11(E) tell you what you need to know. What part of it don't you understand?

 

[hhsting]

422.11(E) tell you what you need to know. What part of it don't you understand?

I dont get is non continuous load only your suppose to size feeder 100% and the size breaker based on feeder.

Now comes 422.11(E) so for any motor non operated load not just water heater now we change definition of continuous load and can have 150% instead if 100%?

 

[david luchini]

I dont get is non continuous load only your suppose to size feeder 100% and the size breaker based on feeder.

Now comes 422.11(E) so for any motor non operated load not just water heater now we change definition of continuous load and can have 150% instead if 100%?

You asked about branch circuits, not feeders.

And nothing in 422.11(E) changes the definition of continuous load.

 

[augie47]

Your original question was concerning the over-current protection on an appliance (instant water heater) .. the Code reference addresses that issue The question, which has been asked by you previously and answered, was addressed and the thread closed.

 

[hhsting]

You asked about branch circuits, not feeders.

And nothing in 422.11(E) changes the definition of continuous load.

Same deal with branch circuit. non continuous load only your suppose to size branch circuit 100% and the size breaker based on branch circuit


Now comes 422.11(E)(3) changes non continous load percentage to 150%. How? Instant hot water heater is non continue load how more than 100% applies to this and 422.11(E)(3) both contradict each other


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[petersonra]

It does not change the load at all. It just allows you to size the CB at 150%.

 

[LarryFine]

I dont get is non continuous load only your suppose to size feeder 100% and the size breaker based on feeder.

At least that size; may be larger. The code is mostly about minimums.

That's why we can use 30a breakers on 4500w water heaters.

 

[david luchini]

Same deal with branch circuit. non continuous load only your suppose to size branch circuit 100% and the size breaker based on branch circuit

There's no Code section that says that.

 

[Fred B]

422.11 gives you a few options based on appliance label. If Information is given in specifications as to a breaker size, use that (422.11(A). 422.11(B,C,D) doesn't apply to your appliance in question 422.11(F) doesn't apply as not over 48A. You are left with complying with 422.11(E) as others have stated. 422.11(E)(3) does not say you must size to 150%, it only allows you to size up to and not more than 150% but will allow for next size up based on standard ratings.
It sounds as if the mfg has told you a 20A breaker and that is what you use. Now wire sizing a different story.

 

[petersonra]

It sounds as if the mfg has told you a 20A breaker and that is what you use. Now wire sizing a different story.

I think a lot of people confuse required conductor ampacity, maximum OCPD rating, and load.

 

[don_resqcapt19]

I dont get is non continuous load only your suppose to size feeder 100% and the size breaker based on feeder.

Now comes 422.11(E) so for any motor non operated load not just water heater now we change definition of continuous load and can have 150% instead if 100%?

How does anything in a section that is titled "422.11 Overcurrent Protection." have anything to do with continuous loads???
There is nothing in that section or any of its seven first level subdivisions that have anything to do with a continuous load. All of the first level subdivisions deal only with subject matter that is related to the title of the section.

 

[wwhitney]

To spell it out, for an individual branch circuit for such an appliance:

422.11(E)(3) specifies the max OCPD rating
210.20 specifies the minimum OCPD rating
210.19 specifies a minimum conductor ampacity
240.4 specifies a required relationship between OCPD and ampacity.

So you could start with the 210.19/210.20 minimum ampacity and OCPD values. Then if you want you can increase the OCPD up to the maximum value specifies in 422.11(E)(3), but you have to increase the ampacity accordingly per 240.4.

Cheers, Wayne