Infratech heater control

eds

Senior Member
Will be installing a 6kw Infratech (2) 3kw heating elements heater that comes with a stack switch allowing for individual control of each element. Single over current device will be installed, a 2 pole 35. Question is on putting that type of control into a circuit with OCP of 35. Each 1/2 of the switch switch is rated at 20 amps 240v
 

Beaches EE

Senior Member
Location
NE Florida
Occupation
Electrical Engineer / Facilities Manager
Couple of questions. What is the supply voltage and can you post a picture of the nameplate?
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
As an assembly, we're not responsible for the design of the internal wiring.

Is a range required to have each burner's control capable of 40 or 50 amps?
 

eds

Senior Member
Supply voltage is 240, don’t have a picture of nameplate, as of now all info being taken from their website. Switch wiring will likely be 3 wire setup. I could set it up as separate breakers for each element, but their tech support tells me that the NEC doesn’t allow that. I will need to verify that for myself. I suppose in use of a stack switch I couldn’t have separate feeds landing on one yoke without being able to disconnect all at same time.
 

texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
As an assembly, we're not responsible for the design of the internal wiring.

Is a range required to have each burner's control capable of 40 or 50 amps?
I think in this case the stack switch is field installed and located. While the load on each switch is below the rating I'm not sure this is compliant as shown in the diagram posted by the OP.
 

eds

Senior Member
what am i missing here 35 amp ocp, with each part of the stack switch rated for 20 amps
 

texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
It appears to be convertible. Just follow the 3-wire instructions.
Look closely at the diagrams. One is for a heater with 2 elements and the other is for 2 separate heaters-not convertible.
As I said in post 7, I don't think this is NEC compliant. I think if the stack switch was part of the listed heater that would be different than a field installation of the switch external to the heater as shown.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Ah, my mistake. I thought it was two diagrams for the same unit.

So, the question is whether it's compliant to follow the manufacturer's instructions?

I'm not tempted to say no, it isn't, and two 20a circuits (handle-tied to use a duplex switch) is the cure.

Unless you can get something from the manufacturer that allows 20a switches on a 35a breaker.
 

texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
Ah, my mistake. I thought it was two diagrams for the same unit.

So, the question is whether it's compliant to follow the manufacturer's instructions?

I'm not tempted to say no, it isn't, and two 20a circuits (handle-tied to use a duplex switch) is the cure.

Unless you can get something from the manufacturer that allows 20a switches on a 35a breaker.
He has 25 amps of load at 240.
 

texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
Another issue with the diagram is the disconnecting means. They are only breaking one side of the circuit. OK for control but not disconnecting means. Have to look it up but I think a breaker lock would solve that.
 

eds

Senior Member
just thinking out loud tonight, what prevents me from utilizing (2) single throw double pole 20 amp switches with a 2 pole 20 feeding each element? Each switch would be in sight of the controlled load. As of tonight I cannot think of a NEC violation. Possibly a listing violation?
 
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