Commercial Feeder Question

[mkgrady]

I'm trying to determine if a feeder to a spa is of adequate size. The spa will provide services such as massage, sauna, steam, facials, nails and all that girly stuff. Figuring a feeder/panel size in a commercial space is new to me.

The spa has there own 100 amp 120/208 three phase panel from their own meter. I get 208*100*1.73 for a total of 36KW. The space is 2200 square feet.

The biggest loads are two steam units (8kw each), sauna(2800w), A/C(7200w), combo washer dryer, microwave, a couple of exaust fans that will pull steam out of the steam rooms, washer/dryer combo, DW, Water Heater and lighting.

When I plug in my estimates of the individual loads I get 43KW and that doesn't even address which loads are continuous.

If I assume all loads are continous I figure a 150 amp panel is required. In reality the steam units are not continous but at least I get a cushion. Am I doing this right?

Mike

 

[mdshunk]

Sure sounds like you're over the limit for the size panel you have there now. While your method might not be quite "normal", it's quick and accurate enough to at least determine if what you have there now will suit or not; which it clearly won't. What sort of equipment is feeding this panel? Often, that can be a really limiting factor. This can make the difference between a relatively cheap 100 to 200 amp feeder and panel change, or some rather expensive changes at the building's service equipment.

 

[mkgrady]

What sort of equipment is feeding this panel? Often, that can be a really limiting factor. This can make the difference between a relatively cheap 100 to 200 amp feeder and panel change, or some rather expensive changes at the building's service equipment.

Thanks for confirming my thinking.

What is there is a relatively new UG service with three meters. One of the three is the landlord who occupies space and I assume he carries the house panel. Each of the three occupants have a 100 amp feeder. The landlord includes the normal stuff in common areas and an elevator on his panel plus his own small space. The last occupant is a sporting/clothing store.

Because this spa is going to use considerably more power than the last occupant (dentist) I wonder if the building service needs upgrading. Trouble is I don't know where to strat to figure that out. I looked at NEC 220 and my brain started to hurt.

 

[mdshunk]

Because this spa is going to use considerably more power than the last occupant (dentist) I wonder if the building service needs upgrading. Trouble is I don't know where to strat to figure that out. I looked at NEC 220 and my brain started to hurt.

Meter stack, or nippled out of a gutter? If it's a gutter type service, open the gutter and take a look-see at what it's fed with. Might be as simple as changing the meter can and the tap conductors. You next call should be to the PoCo engineer or lines designer to see how much headroom you have on their lateral feeding that meter arrange (assuming it's their lateral). Even if it is a meter stack, there's often places inside them to bolt lugs on the bus to hang a big meter of your own off it, nippled out of the side. If it was me, I'd probably meet with a PoCo guy on site as a next step. Between now and then, try to pin down your demand load calc a little better so that you guys have real numbers to talk about.

 

[cadpoint]

& while your at it...

& while your at it...

Meter stack, or nippled out of a gutter? If it's a gutter type service, open the gutter and take a look-see at what it's fed with.

Get a cut sheet of the meter stack too, found out that there is a differance of 8" on GE's - the difference of 125 amp meter and a 200 amp meter base... and the customer has design issues, and the trough is already to tight at the bottom to change...for free ...

 

[mkgrady]

Meter stack, or nippled out of a gutter? If it's a gutter type service, open the gutter and take a look-see at what it's fed with. Might be as simple as changing the meter can and the tap conductors. You next call should be to the PoCo engineer or lines designer to see how much headroom you have on their lateral feeding that meter arrange (assuming it's their lateral). Even if it is a meter stack, there's often places inside them to bolt lugs on the bus to hang a big meter of your own off it, nippled out of the side. If it was me, I'd probably meet with a PoCo guy on site as a next step. Between now and then, try to pin down your demand load calc a little better so that you guys have real numbers to talk about.

It's a meter stack. Actually the meters run sideways. Three 100 amp CB' in 3R enclosures are connected below the bank that feed each tenant. Would it be common that I could just remove the 100 amp and put in a 200 amp?. I realize this may be more that the UG lateral can handle, but maybe the lateral is good for 400 amps.

I'll work on the load calcs. I guess I have to do the whole building unless the lateral is clearly big enough. I'll just have to study 220 till I know how to do it.

 

[mkgrady]

Get a cut sheet of the meter stack too, found out that there is a differance of 8" on GE's - the difference of 125 amp meter and a 200 amp meter base... and the customer has design issues, and the trough is already to tight at the bottom to change...for free ...

Good point, I might as well have all the specs and options on the meter bank.

 

[mdshunk]

It's a meter stack. Actually the meters run sideways. Three 100 amp CB' in 3R enclosures are connected below the bank that feed each tenant. Would it be common that I could just remove the 100 amp and put in a 200 amp?.

Oh, no. I seriously doubt it. Your first stop there would be to determine the manufacturer and model number of the meter stack to see what the busing for each position is rated at. If it's only 100 amp rated, then you're stuck. FWIW, I've never seen a horizontal 3-phase meter stack. Not to say that's not what you have there, but you might want to double check that you really do have 3-phase, unless you're already sure.

 

[mkgrady]

FWIW, I've never seen a horizontal 3-phase meter stack. Not to say that's not what you have there, but you might want to double check that you really do have 3-phase, unless you're already sure.

I was told it was three phase. Not that that means a thing. I think I noticed a three phase CB feeding the elevator but I have no other info. I will certainly double check.