i really need help on this

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nafis

Senior Member
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Palestine,tx
Hi there ,

Here I go .

I do have two appliances
Cook top which is rated (120/ 240) 7200 watt and
Oven rated (120/240) 3400 watt.
The existing wire is # 8 AWG with 40amp breaker .
I add up the total amp, 44.2amp for both

.
My question is can these two load share the same branch circuit. I was thinking of change the circuit breaker to 50 amp breaker and install both of them on the same branch ckt . I figured # 8 AWG is rated 40 amps @ 60 deg and 50 amp @75 deg. Since the panel and appliances is rated for 75deg just assuming . i am trying not to run new ckt . can i do this and what is the safe approach .

I greatly appreciate your in put
 
Keep in mind that the allowable ampacity on your supply cables may be limited to 60o (NM prior to '08 and 'NM & SE in '08).
That said, if I am correct, and I did my math right according to 220.55, you don't have a problem.
Hopefully someone will check that for us.
 
First-- Check out T220.55 Note 3. Then read 210.19(A)(3) Except. 1. Also if this is a residence the wire is probaby nm cable and must be used at 60C. Is this cable a 4 wire cable?
 
I have never seen or heard of2 appliances sharing the same circuit. I don't think you can do that although I don't have a code book in front of me to prove it. I wouldn't do it.
 
steelersman said:
I have never seen or heard of2 appliances sharing the same circuit. I don't think you can do that although I don't have a code book in front of me to prove it. I wouldn't do it.
Click to expand...

YOu wouldnt do it because you lack the understanding of it.
 
augie47 said:
That makes it a 40 amp cable, but I think under 220.55 you are o.k.
Dennis, am I correct ?
Click to expand...

Table 220.55 will definitely allow it. I don't quite understand 210.19(A)93) excep. 1. Does that mean I must have a 50 amp cir. to do this or is it saying if I use a 50 amp branch circuit....

I have seen it done many times before. I am not certain of what art. to help with here.
 
steelersman said:
your right, I have a total lack of understanding and knowledge and have no right to offer my humble opinion.
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opinions are welcomed..for the most part, opinions is all most of us offer here. having put my head in that ole noose many a time (and possibly here again when dennis mention the wording on the exception), I can only suggest , unless you have REAL thick skin, look at the Code first.:smile:
 
nafis said:
i have never done it before , my calu said i can . but i would like to hear your opinions on this ...
Click to expand...

even the best of us might not be able to shoot that one full of holes :smile:
 
nafis said:
Hi there ,

Here I go .

I do have two appliances
Cook top which is rated (120/ 240) 7200 watt and
Oven rated (120/240) 3400 watt.
The existing wire is # 8 AWG with 40amp breaker .
I add up the total amp, 44.2amp for both

.
My question is can these two load share the same branch circuit. I was thinking of change the circuit breaker to 50 amp breaker and install both of them on the same branch ckt . I figured # 8 AWG is rated 40 amps @ 60 deg and 50 amp @75 deg. Since the panel and appliances is rated for 75deg just assuming . i am trying not to run new ckt . can i do this and what is the safe approach .

I greatly appreciate your in put
Click to expand...

Howdy,

Lets assume 2005 NEC .

If you have a single cooktop and single oven...see 220.55,Note 4

Add up the nameplate ratings of both appliances, then use column C which would be 8KW.......use 8KW and you have 33A. Then 210.19(A)(3) explains the branch circuit conductors sizing needs. if using NM Cable then 60 degree column in 310.16 for conductor sizing. So to me you # 8 AWG is fine.

Now...I guess the argument can come from 240.4(B) and say it should be on a 35A breaker...since it is not over 8 3/4KW it does not require a minimum of a 40A circuit breaker per 210.19(A)(3) in the last part of it anyway...lol
 
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just a bit of info, years ago i ran into the same exact situation, and i calculated and read the code, and supplied both appliances of the one circuit, and i fell short a month after the install the breaker started tripping at 40 amp, to be on the safe side i would run two seperate circuits. sorry just wanted you to know my trouble
 
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