The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!

Featured:
   

2017 NEC and Related
2017 NEC
Now Available!

   
Recent Posts
Sprinklered equipment 26-008
by bigpapa
12/02/16 04:24 PM
On Delay Relay with Auto Reset
by Potseal
12/01/16 09:59 AM
Wow, that was close!
by jraef
11/28/16 07:06 PM
Earthquake in New Zeeland
by RODALCO
11/27/16 11:25 PM
Calling all Non-US members!! (Non-US only)
by Tjia1981
11/27/16 06:33 AM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 15
HotLine1 10
Trumpy 8
Texas_Ranger 8
sparkyinak 7
Who's Online
1 registered (sparkyinak), 237 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#68395 - 08/05/06 03:27 PM Sizing a disconnect for a Unit Heater
Cinner Offline
Member

Registered: 12/01/04
Posts: 77
Loc: Kelowna, B.C., Canada
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?

Top
Work Gear for Electricians and the Trades

Work Gear for Electricians and the Trades
Work Gear for Electricians and the Trades
Arc Flash Clothing, Gloves, KneePads, Tool Belts, Pouches, Tool Carriers, etc. etc....

#68396 - 08/05/06 04:10 PM Re: Sizing a disconnect for a Unit Heater
Tom Offline
Member

Registered: 01/01/01
Posts: 1069
Loc: Shinnston, WV USA
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)
_________________________
Few things are harder to put up with than the annoyance of a good example.

Top
#68397 - 08/09/06 07:47 PM Re: Sizing a disconnect for a Unit Heater
RobbieD Offline
Member

Registered: 02/23/03
Posts: 238
Loc: Canada
15 Amp three phase breaker

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

Top



ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals