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
breaker meltdown
by sparky
Yesterday at 07:30 PM
230 or 345 kV transmission lines?
by Vlado
09/24/16 09:33 AM
Electrical mast flashing product
by ThomasWinfrey
09/22/16 12:14 AM
What estimating software do you recommend?
by sparky
09/21/16 07:20 PM
"Dry Run" Inspection goes awry
by HotLine1
09/20/16 07:39 PM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
HotLine1 13
sparky 10
gfretwell 8
sparky66wv 8
Vlado 6
Who's Online
0 registered (), 254 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#189090 - 09/18/09 04:15 PM Gas furnace MCA and MOCP
jem Offline
New Member

Registered: 04/30/07
Posts: 8
Loc: nc
I have been coming accross these Heil brand gas furnaces that do not have the MCA and MOCP on the nameplate. They list the maximum input current which I think is what the unit is rated. How do I calculate these values.

Top
2014 / 2011 NEC & Related Books and Study Guides
#189091 - 09/18/09 04:25 PM Re: Gas furnace MCA and MOCP [Re: jem]
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9012
Loc: Estero,Fl,usa
This usually applies to HVAC compressors. Does this furnace have anything more than a blower, igniter and some controls?
When in doubt use 310.16 and 240.4(D)
_________________________
Greg Fretwell

Top
#189106 - 09/19/09 11:09 AM Re: Gas furnace MCA and MOCP [Re: gfretwell]
jem Offline
New Member

Registered: 04/30/07
Posts: 8
Loc: nc
There is also a small combustion blower.

Top
#189109 - 09/19/09 01:31 PM Re: Gas furnace MCA and MOCP [Re: jem]
George Little Offline
Member

Registered: 01/18/04
Posts: 1492
Loc: Michigan USA
Look at the manufacturer's installation guide for the furnace. Usually they will tell you what size circuit. Some even tell you what size wire to run and depending on the length of the run they may have you increase to the next size wire. I'm seeing some of your larger furnaces specify a 20a. circuit.
_________________________
George Little

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