Microwave ovens and articles 220.53 and 220.55

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Tainted

Tainted

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Are microwave ovens subject to 220.53 or 220.55?

I know without a doubt that regular microwaves are subject to 220.53 but not sure about microwave ovens.

220.55 calls for ovens and that means microwave ovens technically apply?

If it is less than 1750W then it means I cannot use table 220.55 therefore I must count it as 100%?
 
Tainted said:
Are microwave ovens subject to 220.53 or 220.55?

I know without a doubt that regular microwaves are subject to 220.53 but not sure about microwave ovens.

220.55 calls for ovens and that means microwave ovens technically apply?

If it is less than 1750W then it means I cannot use 220.55 therefore I must count it as 100%?
Click to expand...

Are you talking about a regular oven with microwave ability, otherwise I don't get the difference between the two appliances
 
So it is a single unit with a microwave and an standard oven? The power supply I assume is a standard branch circuit.

I don't think you can get any help from T. 220.55

One note states that for one oven use the nameplate so I see 1 oven and a mw and each should be calculated as oven at nameplate
 
Dennis Alwon said:
So it is a single unit with a microwave and an standard oven? The power supply I assume is a standard branch circuit.

I don't think you can get any help from T. 220.55

One note states that for one oven use the nameplate so I see 1 oven and a mw and each should be calculated as oven at nameplate
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So you don't think it's an "appliance fastened in place"?

and we should calculated it at 100%? it's 1650Watts
 
Tainted said:
So you don't think it's an "appliance fastened in place"?

and we should calculated it at 100%? it's 1650Watts
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Imo, yes. Any built in microwave is figured at 100%. And the oven is nameplate rating so just because they are on the same branch circuit I would calculate at 100%. Not sure if the code offers any opinion and the option. I am certain the unit as one has a nameplate and that is what I would use.
 
Tainted said:
So you don't think it's an "appliance fastened in place"?

and we should calculated it at 100%? it's 1650Watts
Click to expand...
At 1.65 kW, 220.55 clearly doesn't apply; it is restricted to cooking units 1.75 kW and larger. But I see no reason that 220.53 doesn't apply.

Cheers, Wayne
 
wwhitney said:
At 1.65 kW, 220.55 clearly doesn't apply; it is restricted to cooking units 1.75 kW and larger. But I see no reason that 220.53 doesn't apply.

Cheers, Wayne
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I think 220.55 applies but must be counted as 100% since it's less than 1.75kW. It has convection capability...

This is why I hate combo units, whoever wrote the code did not consider combo units...
 
Tainted said:
I think 220.55 applies but must be counted as 100% since it's less than 1.75kW.
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I will agree it meets all the qualifiers of the first sentence of 220.55 other than "rated in excess of 1.75 kW." Failing to meet that qualifier means 220.55 doesn't apply. You never get a demand factor from 220.55 for it other than 100%, and the presence or absence of it never changes the group demand factor under 220.55 for other ovens.

It is odd that a single 1.75 kW oven gets to use a demand factor of 80%, so it counts as 1.4 kW, while a single 1.65 kW oven doesn't get to use a demand factor, so it counts as 1.65 kW. Maybe there's an argument for imaginary rerating of the oven to 1.75 kW.

Cheers, Wayne
 
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