Fire Water Tank Heaters

[Sparky2791]

Have a stand alone fire water tank which will have (2) 10kW heaters inside the tank. Each with separate controls no disconnecting means provided with the tank heaters by the manufacturer. This tank will be sitting about 15' away from the buildings electric room. I assume each of these heaters to require a disconnect switch at the tank. What NEC code section would justify this requirement for this type of situation.
Thanks for the replies!

 

[steve66]

I believe a padlock attachment at the branch breaker also works.

There is a section in chapter 4 that covers heating vessels. Or some might consider it an appliance.

 

[don_resqcapt19]

427.55

 

[petersonra]

427.55

I have always found it curious that electric water heaters seem to be covered in article 422, since it specifically refers to them there, which would make them an appliance, although by description they belong in article 427.

 

[steve66]

I have always found it curious that electric water heaters seem to be covered in article 422, since it specifically refers to them there, which would make them an appliance, although by description they belong in article 427.

If its a listed, packaged hot water heater, I would say 422 covers it.

427 seems to be more for industrial equipment - tanks and pipes that could be fabricated on site or custom made. 427 doesn't seem to require the same listing that 422 does.

But the disconnect rules seem to be similar in either section.

 

[don_resqcapt19]

I have always found it curious that electric water heaters seem to be covered in article 422, since it specifically refers to them there, which would make them an appliance, although by description they belong in article 427.

Yes, the typical electric water heater used in residential and commercial applications is an appliance.

However the original post talks about heating a fire water tank. I am assuming this is a large storage tank that is a static water source for a fire sprinkler system and needs freeze protection. I believe that would be covered by the rules in 427 and not 422.

 

[Sparky2791]

Yes, the typical electric water heater used in residential and commercial applications is an appliance.

However the original post talks about heating a fire water tank. I am assuming this is a large storage tank that is a static water source for a fire sprinkler system and needs freeze protection. I believe that would be covered by the rules in 427 and not 422.

You are correct, for freeze protection. Thanks for the replies!

 

[don_resqcapt19]

You are correct, for freeze protection. Thanks for the replies!

Note, where electric heat tape is used to provide freeze protection for fire sprinkler piping, it must be specifically listed for that purpose. I don't know if there is a requirement like that for freeze protection of a fire water storage tank.

 

[Sparky2791]

Note, where electric heat tape is used to provide freeze protection for fire sprinkler piping, it must be specifically listed for that purpose. I don't know if there is a requirement like that for freeze protection of a fire water storage tank.

No worries its not electric heat tape its actually heaters that are inserted into the tank.

 

[don_resqcapt19]

No worries its not electric heat tape its actually heaters that are inserted into the tank.View attachment 2562611

My comment said I did not know if the tank heaters had to be specifically listed for that purpose...would probably have to look to NFPA 13 to find out.