Load calcs for new service before building plans exist?

[Todd0x1]

How would one go about doing load calcs for non existent residential structures? Here's the situation: Residential property, will eventually get a 3600 sq/ft house, a 600 sq/ft ADU, a ~1000 sq/ft garage, a small pool building with bathroom,1x electric car charger, and a dedicated utility building housing electrical (service, ATS, generator distribution panel, panel for outdoor circuits, lighting controls, solar inverters, space for batteries maybe) and data. These structures will be designed and developed over time. I want to get the electrical service in at the start of the project, then feed the buildings from it as they're built. Service would be a 400 amp switchboard w/ 600 amp buss. PoCo obviously wants plans and a load calc. What should we do? Make a load calc based on assumptions of what would go in the buildings?

Also, is there another term for the small padmount transformers used in residential distribution? Lines are overhead, there is 5kv on the side of the property I want the PoCo to use one of these small padmounts and feed the service underground as we're trying to not have a giant pole mount transformer in the yard. Mentioned padmount to poco engineer and he started this tirade about clearances, room for a crane, 8ft clearance with bollards around all sides of the transformer which sounded more like for the larger commercial service padmounts, not the little 25kva ones that can be placed with pretty much anything.

 

[LarryFine]

All you can do is guesstimate based on lighting and HVAC (all-electric?) by area, appliance list, etc.

I'm not very familiar with solar and batteries (but I'm willing to learn), so I can't advise there.

Two 200a panels, one on the genny, one not, might be simpler, at least for a "normal" service.

 

[drktmplr12]

I believe Eaton sells those small residential, 1-phase pad mounts. Don't know of a name other than pad mount.

Conventional single-phase pad-mounted transformer

Eaton’s Cooper Power series conventional single-phase pad-mounted transformers offer a Bay-O-Net overcurrent protection fuse and are available in a variety of sizes and options to meet varied customer requirements.

www.eaton.com

If the POCO refuses a pad mount, you could consider doing primary voltage service and have the homeowner purchase/maintain the transformer. Not ideal but certainly an option.

 

[Todd0x1]

I believe Eaton sells those small residential, 1-phase pad mounts. Don't know of a name other than pad mount.

Conventional single-phase pad-mounted transformer

Eaton’s Cooper Power series conventional single-phase pad-mounted transformers offer a Bay-O-Net overcurrent protection fuse and are available in a variety of sizes and options to meet varied customer requirements.

www.eaton.com

If the POCO refuses a pad mount, you could consider doing primary voltage service and have the homeowner purchase/maintain the transformer. Not ideal but certainly an option.

Interesting, I have a feeling the poco here either wouldnt do it or would make it very difficult or expensive. I've seen these small padmounts on larger houses so I know they do it. I was thinking I didn't call it the right thing when I was talking to the poco engineer.

 

[gadfly56]

Interesting, I have a feeling the poco here either wouldnt do it or would make it very difficult or expensive. I've seen these small padmounts on larger houses so I know they do it. I was thinking I didn't call it the right thing when I was talking to the poco engineer.

That can happen. My dad used to call it, "waving your hands over the phone".

 

[Todd0x1]

That can happen. My dad used to call it, "waving your hands over the phone".

Exactly. I'm thinking when he sees the plans he'll say something like "oh you want a dip feed with a green top low boy"