I'm not to "up" on tap conductors. I have a customer that is building a house. For now he wants just a "free standing" range, but later is going to change it to an "in wall oven" and "surface unit" in a counter top. If I pull 8/3 wg to the "free standing range" then later set a junction box and come out of each one with 10/3 wg to the oven and surface unit, will this meet code for "tap conductors? The conductors will just be approx. 6 or 7 feet. from the junction box. The free standing range will be on a 40 amp breaker.
IMHO
If the future whip is only 6 or 7 feet in length, I'd just go ahead and install it as 8/3 instead of 10/3. It's not worth risking getting in a future argument with an AHJ over 10 feet of wire that only saves 1 trade size.
If you replace the breaker in the panel, the 10/3 would fall under the tap rules. My only concern would be as an inspector would be the range top junction box would be suitible for the larger, stiffer 8/3.
Taps still require the proper O/C protection for the conductor. The difference is the O/C device can be on the load end of the tap.
I just re-read the op. when all dead and done, they will be a free standing and a range top on the same circuit? If that is the case, you will need to calculate the load together or just pull in a seperate 10/3 during the rough in.
Huh? I believe this practice has been allowed for years. Read section 210.19(A)(3) exception No.1
This is from 2011 NEC:
Exception No. 1: Conductors tapped from a 50-ampere
branch circuit supplying electric ranges, wall-mounted
electric ovens, and counter-mounted electric cooking units
shall have an ampacity of not less than 20 amperes and
shall be suffıcient for the load to be served. These tap conductors
include any conductors that are a part of the leads
supplied with the appliance that are smaller than the
branch-circuit conductors. The taps shall not be longer
than necessary for servicing the appliance.
There are nice graphics in the Handbook, but...the Handbook seems to be no longer available in an electronic format.
Kevin, when all is said and done, there will be 1 wall mount oven, and 1 surface unit. I guess my question was, can the oven and surface unit still have a 40 amp breaker in the panel to protect them if #10 wire was branched off of a junction box? I know that was done years ago, but didn't know if it still was allowed. Been a while since I've had to do that, but I think John answered my question in the post above.. Thanks
I am with John. I missed that one.
Kevin, when all is said and done, there will be 1 wall mount oven, and 1 surface unit. I guess my question was, can the oven and surface unit still have a 40 amp breaker in the panel to protect them if #10 wire was branched off of a junction box? I know that was done years ago, but didn't know if it still was allowed. Been a while since I've had to do that, but I think John answered my question in the post above.. Thanks
Things have not changed from years past. The #10 would be OK under most circumstances. It depends on the KW rating of the appliances. You have to apply the demand factors as outlined in 220.55 including the notes...
If there will be both a wall mount oven and a surface unit, I would power them separately. Using a single OCP sounds like a great idea until the family gets invited over for a holiday dinner and supper is cooking on the range at the same time that the cake is baking in the oven.
I would not consider the 2 cooking appliances to be non-coincidental loads.
Even if this works right now for your family situation, what kind of problems are you setting up for whoever eventually buys your house down the road?
Here is an example of 2 appliances...
1. GE cooktop model #JP336DDBB ($649) 7.4KW
2. GE single wall oven model #JT3000DFBB ($1399) 4.2KW
Total KW=11.6
Using 220.55 column B along with Note #3 for 2 appliances we can multiply 11.6kw(7.4+4.2) x 65%= 7.54KW
7.54kw / 240volt= 31.42amps
31.42amps is good on a #8wire with a 40amp breaker.