Panel feeder size for panel with multiple freezers on it

[mshields]

I've got an optional standby panel with something like 16 -80 freezers on it (they happen to be 208V-sinlge phase and approximately 2kVA each). I generally, in keeping with Article 440.22, take these at 100% of their nameplate rating. I have a couple of questions.

1) Am I correct that there is no allowance in the code for applying a diversity factor. Realistically, the compressors cycle on and off and I know that when you put a meter on such panelboards, the actual demand load is consistently below 40% of the connected load.

2) If the code provides no relief here, as a practical matter, I'd be interested in the groups experience with regard to the actual demand load seen from such a panel.

Much appreciated,

Mike

 

[chris kennedy]

something like 16 -80 freezers on it

Typo there Mike?

See 430.26 via 220.50, as the EE you may be able to swing this.

On the off chance that there are 16-80 compressors in a commercial kitchen see 220.56.

 

[mshields]

Chris, There are quantity 16, minus 80 freezers on a single panelboard and this is in a lab. Whether you understood that or not, clearly 430.26 is particularly useful. Thankyou! Did some more research and found that these particular freezers had a 25/25 duy cycle. 25 minutes "on"/25 minutes "off" with the door closed. It seems to me taking into consideration that it might not be a perfect 50/50 split at any given time and that doors are occaisionally opened, a 70% demand factor seems reasonable. Would you agree?

Thanks alot Chris!

 

[gfretwell]

Bear in mind, unless you have some kind of delayed start, they will all hit the service at once after a power failure.

This is not like a bunch of ranges, it is an unattended load and they will all hit at once if they get above -80.

It might actually take a while to get them out of sync again.

 

[mshields]

An excellent point! Although these are all generator backed and if they're down more than a matter of seconds, they've got bigger trouble.

 

[chris kennedy]

Chris, There are quantity 16, minus 80 freezers

Gotcha, Revco's?

Mike you can post the degree symbol in a post by holding down the Alt key and hitting 0176 on the right hand keypad. Your post will read;

"16 -80°F freezers".