multiple range outlets

[wiz2007]

I have 10 ranges that are rated @ 8kw each. I have a 3 phase 208v service. Can I use table 220.55 and figure the demand factor for 10 ranges to be @ 25kW?What size of sub - panel do i need to set to feed these ranges?

 

[Dennis Alwon]

Are these ranges used for instructional purpose?

 

[Dennis Alwon]

If these are for other than instructional or household you need to use Table 220.56

 

[wiz2007]

the range outlets are going to be installed in a multi - dwelling unit

 

[Jomaul]

Why wouldn't you use 220.55? I believe the second paragraph would apply? 220.56 deals with commercial kitchen appliances. This sounds like it would be muilti family.

 

[Dennis Alwon]

Why wouldn't you use 220.55? I believe the second paragraph would apply? 220.56 deals with commercial kitchen appliances. This sounds like it would be muilti family.

Read my post. I did not know they were household units.I said "IF". I agree Table 220.55

 

[Dennis Alwon]

If the units are 8kw then you would use col. B

 

[Jomaul]

I don't think you use the table. The load is calculated on the basis of twice the maximun number connected between any 2 phases.

 

[Dennis Alwon]

I stand corrected I missed the 3 phase thing. Art. 220 55

Sorry

 

[Jomaul]

not a problem your one of the guys that is making me understand the code better and I thank you for it

 

[wiz2007]

so what size of sub panel should i set to handel the load of the 10 ranges?

 

[kbsparky]

Show us your work first !!!

Show us your work first !!!

Show us your calculations and what you came up with first, before we post answers for homework questions. If this is an actual project, this same procedure applies.

 

[Dennis Alwon]

Wiz

As you can see some at the forum would like to see if you can work it at first before you get the answer.

Don't be afraid to try it and be wrong. This is not such an easy question-- in fact, I believe the whole range calculation setup is cumbersome and difficult to follow to say the least. I still don't have it down pat but then again I never have to do more than one.

 

[Dennis Alwon]

Just to show you the confusion read this thread. It will confuse you but in the end it may help you understand the calculation.

 

[Jomaul]

10 ranges = max 4 ranges conn between any 2 phases
2 * 4 = 8 ranges
8 ranges from table 220.55 col C = 23kw
23,000/ 2 = 11,500watts per phase
11,500 * 3 = 34,500 total load
34,500 / 360 = 95 amps { 360 = 208* 1.732}

would this be the correct .

 

[Dennis Alwon]

10 ranges = max 4 ranges conn between any 2 phases
2 * 4 = 8 ranges
8 ranges from table 220.55 col C = 23kw
23,000/ 2 = 11,500watts per phase
11,500 * 3 = 34,500 total load
34,500 / 360 = 95 amps { 360 = 208* 1.732}

would this be the correct .

OP's question said 10 ranges at 8kw-- I think you need to use col B

36,000 instead of 23,000-- rest looks good.