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

   
Topic Options
Rate This Topic
#35363 - 03/09/04 04:46 PM Oven and cooktop load
Electric Ian Offline
Member
Registered: 02/10/04
Posts: 132
Loc: MA, USA
Given the following:
Wall mounted oven with nameplate rating of 240V, 8KW, 40Amps.
Cooktop with nameplate rating of 240V, 8KW, 40Amps.
Can I run an #8/3 with 40A OCPD to a JBox. Two whips tapped from the JBox, one to the oven and one to the cooktop. Each whip is #10THHN in greenfield?
Table 220.19 note 4 allows the oven and cooktop to be to have their nameplate ratings added together and treated as one range. Thus I effectively have a range with a 16KW rating. For a 16KW range, table 220.19 note 1 applies. This gives me 8KW+[4(.05*8)] =9.6KW. 9.6KW/240=40Amps. Thus, I should be able to use a 40Amp branch circuit to feed both units. Anyone see any problems with this?
Top
Work Gear for Electricians and the Trades
#35364 - 03/09/04 05:29 PM Re: Oven and cooktop load
u2slow Offline
Member
Registered: 09/18/03
Posts: 198
Loc: Salt Spring, BC, Canada
I'm not familiar with the NEC, but aren't standard breakers only to be loaded to 80%?

So 40A * 125% = 50A

That would require #6 wire running to the JB and 50A OCP.

I would size the conductors running to each unit from the JB as though they were each their own range. (That's probably how you arrived at #10 wire?)
Top
#35365 - 03/09/04 06:04 PM Re: Oven and cooktop load
Electric Ian Offline
Member
Registered: 02/10/04
Posts: 132
Loc: MA, USA
I believe the 80% rule you refer to is for continuous loads only. I don't believe a range is considered a continuous load.
Top
#35366 - 03/11/04 04:24 PM Re: Oven and cooktop load
Edward Offline
Member
Registered: 12/14/02
Posts: 309
Loc: California
I would run two dedicated circuits 40A each.

That way i know when they have both of the units on during a party or Thanksgiving cookoff they will not trip the breakers.

Edward
_________________________
Thanks
Edward
Top
#35367 - 03/18/04 10:53 AM Re: Oven and cooktop load
CDN_ELECTRICIAN Offline
Member
Registered: 01/22/03
Posts: 75
Loc: Concord,Ontario,Canada
I think the approach is wrong, here!

Electric Ian your looking at the rules for "Calculating Demand Factors" which basically used for calculating Total Loads.

Edward is correct, the rules that would apply would be rules that relate to Protection of Conductors and Equipment. (fusing)

Due to this, each unit gets a seperate feed, unless the unit comes with protection for the remote unit buit-in.
Top

Featured:

2017 NEC and Related
2017 NEC
Now Available!

Shout Box

Recent Posts
License exam
by TRUE POWER
48 minutes 0 seconds ago
Looking for older post
by sparkyinak
Today at 12:27 AM
Members: Non-Members: Did you know?
by Admin
Yesterday at 02:34 PM
Safety at heights?
by HotLine1
01/21/17 08:51 PM
International Wire Colour Codes
by Texas_Ranger
01/21/17 03:29 PM

Who's Online
1 registered (Admin), 92 Guests and 10 Spiders online.
Key: Admin, Global Mod, Mod
New in the Gallery:
Desk-mounted "power-board"
Top Posters
gfretwell 9066
Trumpy 8560
pauluk 7693
HotLine1 6833
sparky 5545
Member Spotlight
Member Since: 03/13/07
Posts: 167

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