ECN Forum
Posted By: Cinner Sizing a disconnect for a Unit Heater - 08/05/06 10:27 PM
A 3000 watt unit heater is to be installed in a storage room...it has a fan built in... but is does not have a HP rating...3 phase 208 volts...what size disconnect is required?
Posted By: Tom Re: Sizing a disconnect for a Unit Heater - 08/05/06 11:10 PM
The motor load for a unit heater this small is unlikey to exceed 1/8th HP. If you were to use a standard safety switch, a 3 pole 30 amp switch would do the trick.

An alternative would be a 3 pole switch such as a Hubbell HBL7810BW. This type of switch is made by others, but that is the only catalog # I have handy. This switch will cost about as much as a safety switch and will probably need to be ordered.

You may not need a disconnect at the heater if the circuit breaker complies with 424.19(B)(1)
Posted By: RobbieD Re: Sizing a disconnect for a Unit Heater - 08/10/06 02:47 AM
15 Amp three phase breaker

[This message has been edited by RobbieD (edited 08-09-2006).]
© ECN Electrical Forums