ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
UL 508A SPACING
by ale348 - 03/29/24 01:09 AM
Increasing demand factors in residential
by tortuga - 03/28/24 05:57 PM
Portable generator question
by Steve Miller - 03/19/24 08:50 PM
Do we need grounding?
by NORCAL - 03/19/24 05:11 PM
240V only in a home and NEC?
by dsk - 03/19/24 06:33 AM
New in the Gallery:
This is a new one
This is a new one
by timmp, September 24
Few pics I found
Few pics I found
by timmp, August 15
Who's Online Now
1 members (ale348), 302 guests, and 14 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
#189090 09/18/09 07:15 PM
Joined: Apr 2007
Posts: 8
J
jem Offline OP
New Member
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.

Stay up to Code with the Latest NEC:


>> 2023 NEC & Related Reference & Exam Prep
2023 NEC & Related Reference & Study Guides

Pass Your Exam the FIRST TIME with the Latest NEC & Exam Prep

>> 2020 NEC & Related Reference & Study Guides
 

Joined: Jul 2004
Posts: 9,923
Likes: 32
G
Member
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
Joined: Apr 2007
Posts: 8
J
jem Offline OP
New Member
There is also a small combustion blower.

Joined: Jan 2004
Posts: 1,507
G
Member
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

Link Copied to Clipboard
Powered by UBB.threads™ PHP Forum Software 7.7.5