Strip Mall Commercial Service Calculation

[andrewselectric]

I have a total sqare footage of 17000 square footage divided up into 13 strip stores for a new strip mall.The problem is the tennant spaces are not leased yet and I have no way of knowing what stores or restraunts will end up occupying the spaces. If I did it would be easy.I have know list of equipment for each store obviously. The gc doesnt want to overkill the service but I dont want to undersize it either.Has anyother EC's run into this problem or anyone for that matter.

 

[mdshunk]

I do a few of these each year. It sorta stinks to be in the position of being an electrical physic. If the units are divided up into standard 35' wide units, it is most normal to serve each 35' cell with a 3-phase, 225 amp panel. Just leave the service gutter extra long for future tenants (such as restaurants) that need a bigger service. If you're using a meter stack, use a modular stack so that a larger metering section can be plugged on the end for a tenant with larger power requirements.

 

[Jim W in Tampa]

Other than for air /heat and lights there is no way of knowing the needs.Bid on minimum client wants.Most leases call for the tenant to pay for any changes.

 

[augie47]

strips

strips

how do you guys approach the smaller "strips" ?
I often encounter a 6 unit "strip" and the EC will install a 600 amp MLO modular meter center with (6) 200 amp breakers and panles with limited load--a few lights and a heat/air unit.
As built the service is more than adequate, but their is obviously potential for a 1200 amp load on 600 amp service conductors...obviously it's not going to get that bad, but their is potential for overloading the service.
I'd be interested in how others approach this.

 

[Dave_PE]

It's definitely an issue, I usually show a basic load calc for each tenant, based on square footage for lighting and receptacles, HVAC, sign circuit, window receptacles, a water heater, and then add a "misc. load" like 10kVA for future and unknown loads per space. Each load calc per tenant usually comes in around 100A or 125A or so at 120/208V 3-ph. Usually works pretty good, and I always stub-up empty conduits from the transformer for future really large tenants if they end up coming in. Most developers know ahead of time how much square footage can be allocated for restaurants vs. office/retail space so you have to ask up front. If a tenant takes multiple spaces, he gets multiple meters. Usually minimum size per space is 200A, 3-ph.

Lately, the AHJ has been making the engineers prove that the metercenter/gutter is not getting overloaded, easy to do if the same EE does all the fit-outs, but can be a paid with multiple EE's, especially if utility demand data is not yet available and you're designing the last tenant fit-out.