Preparing a panel schedule

[Spagedy]

i have to prepare a panel schedule for a 120/208V schedule . i do not have much electrical backround yet. i have list of loads and a template but i just want tips or advice on how to go about approching the problem. maybe a link of a useful site?

 

[dpc]

Or a EE to help? You're probably overthinking it. Your load list needs to distinguish between single phase 120 V loads, single-phase 208 V loads and three-phase 208 V loads. The continuous current (three hours or more) cannot exceed 80% of the breaker rating. So a 20 A breaker can carry only 16 A on a continuous basis. The single phase loads should be distributed to balance out the load between the three phases as much as possible.

But seriously, I think you will need some help from a EE or good electrician to do this the first time.

 

[shamsdebout]

You can find some panel schedules here:

http://www.dcengineers.com/downloads/Panel_Spreadsheets.zip

 

[enverd]

Spagedy,

good explanation from dpc but even a better suggestion to get and EE to help you.
I always appreciate other disciplines showing interest in electrical but to do this right you need someone who knows what they are doing to get things right.

In regards to your question however, DPC explained it well and I would just add to it that all loads have to be reflected in the panel schedule as to what they feed (i.e. circuit 1 is it a 20A, 1pole of 15A 1pole or something else, what load does it feed and in what room). Very imporatant and to reitarete DPCs point the loads have to be balanced to the greatest extent possible. When calculating the final connected load you have to apply the sqrt(3) meaning divide the totatl kW by (208V*sqrt(3) or 360).

 

[JohnMcNutt]

I like that spreadsheet, but it appears that I must use Excel proper to get the calcs to function? Right now I have OpenOffice and I try to keep MS products away as much as possible, but I am not principled in that. I just wish there was another way.

 

[dpc]

There are a million other ways. It's just a table.