Meter Banks with 208V 3 Phase In...

[new_ee]

and 3 phase out.

I want to make sure im doing calculations right.

When I'm determining the load on each of the individual meter banks. I'm mutiplying the amps by 208V and leaving out the 1.73.

Once I've totaled all the individual loads on the meterbank I'm taking the VA total and dividing by 208*1.73 for a three phase load.

Is this right?

 

[jtester]

Re: Meter Banks with 208V 3 Phase In...

post by new ee

When I'm determining the load on each of the individual meter banks. I'm mutiplying the amps by 208V and leaving out the 1.73.

I am not sure what you mean by that, but you would be correct if your individual tenants were metered single phase. If each meter feeds a 3 phase load, the 1.732 would be in all the calculations.

If you want, post a calculation, and perhaps we can help.

Jim T

 

[steve66]

Re: Meter Banks with 208V 3 Phase In...

That should work if the loads are balanced between phases. However, say you only have 4 tenants. Then there might be one tenant on the A-B phase, one tenant on the B-C phase, and 2 tenants on the C-A phase. I think you can see how the C-A phase will have more load, and dividing the total load by 208*1.7 will not give an accurate indication of the load on the C-A phase.

I would keep track of the loads on each phase, and then just divide each one by 208V to get the current.

Steve

 

[new_ee]

Re: Meter Banks with 208V 3 Phase In...

thanks steve. you understood what i was trying to ask. and your answer coincides with what i thought was going on. so if theres 12 tenants with the same load on one main (individual meters/breakers) i just need to map out and keep track of the phases. its kind of hard for the engineer because im not exactly sure what order or how the panels will eventually be connected to the bus bars.