Boilers fault current contribution

[mathan1987]

Hi i am working on a project involving 11 boilers each 20kw, 480v, 3phase rating. I am curious to know what will be the fault current contribution of the boilers. are boilers need to be treated as continuous load (125%) ? Are boilers motor loads or heating loads?

 

[tom baker]

Please see Art 100 definition of continuous load.

 

[winnie]

How much of the rating is motor load?

You say 20kW boiler, which usually means 20kW of resistance heating with no short circuit contribution. But if you have a different type of boiler the answer would be different.

(Does anyone use friction stirring to heat water? )

Jon

 

[David Castor]

If these are electrically-heated resistance boilers, there is no fault current contribution, unless there are pump motors provided with the boilers. There are heat pump type "boilers" - that could be a different issue, but still not likely to be much motor fault contribution.

 

[Jraef]

Gas or fuel fired boilers can have big electric powered ID or FD fans that could be contributors, and those boilers are often still rated in kW or HP, so you need to know what type of boiler you are talking about. Electric resistance boilers will not contribute.

 

[topgone]

Gas or fuel fired boilers can have big electric powered ID or FD fans that could be contributors, and those boilers are often still rated in kW or HP, so you need to know what type of boiler you are talking about. Electric resistance boilers will not contribute.

I am sure electric boilers have a pump to supply water to the steam boiler to maintain safe boiler water levels also.

 

[zbang]

IME feedwater pumps and other auxiliaries aren't usually considered "the boiler" (pressure vessel, heat source, controls; the heat source might have some integral motors). They certainly need to be considered, but they're usually separate items.