Line Side Taps

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DuvNJ

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Marlboro, NJ, USA
What is my limiting factor when designing a line side tap, where one previously exists? Is it simply the bus must be rated higher than the sum of the (2) taps? I realize the feeder to the service transformer, as well as the transformer itself must be taken into consideration...
Any help is appreciated...thanks!
 
DuvNJ said:
What is my limiting factor when designing a line side tap, where one previously exists? Is it simply the bus must be rated higher than the sum of the (2) taps? I realize the feeder to the service transformer, as well as the transformer itself must be taken into consideration...
Any help is appreciated...thanks!
Click to expand...

I think you need to be more specific. Are you adding another source to the same tap, or planning to add power to the normal service panel or somewhere else? What bus are you referring to?

What we can tell you...

- The total sum of interactive sources connected to the service shouldn't exceed the rating of the service.
- Other than that, nothing about the line side tap should have any bearing on connecting anywhere else.
 
Thanks for replying....

Would be adding an additional source (both sources PV) ahead of the MCB ...but via a 2nd Tap (not adding to the first). This would be in the Main Switchgear, after the Utility CT/PT section but again, before the Main Circuit Breaker. To Put some real numbers to it...

The Main Bus is rated at 3000A; the existing tap is for a fused Disconnect (for a PV Array) rated at 1000 A. Does that give me 2000A of capacity of additional Solar? (Again, this is assuming the Service from the Utility Transformer is sized to handle the full bus capacity.....)

Thanks again
 
DuvNJ said:
Thanks for replying....

Would be adding an additional source (both sources PV) ahead of the MCB ...but via a 2nd Tap (not adding to the first). This would be in the Main Switchgear, after the Utility CT/PT section but again, before the Main Circuit Breaker. To Put some real numbers to it...

The Main Bus is rated at 3000A; the existing tap is for a fused Disconnect (for a PV Array) rated at 1000 A. Does that give me 2000A of capacity of additional Solar? (Again, this is assuming the Service from the Utility Transformer is sized to handle the full bus capacity.....)

Thanks again
Click to expand...

The way I might do it is to combine the inverter outputs in an AC combiner panel and beef up the switch. Your AHJ may not allow you to have two taps on the same service.
 
DuvNJ said:
Thanks for replying....

Would be adding an additional source (both sources PV) ahead of the MCB ...but via a 2nd Tap (not adding to the first). This would be in the Main Switchgear, after the Utility CT/PT section but again, before the Main Circuit Breaker. To Put some real numbers to it...
Click to expand...

230.40 Exception 5 specifically mentions 'one set of service conductors' for 'each or several' PV systems. So I guess that allows this. I agree with ggunn though. Consider which is easier.

The Main Bus is rated at 3000A; the existing tap is for a fused Disconnect (for a PV Array) rated at 1000 A. Does that give me 2000A of capacity of additional Solar? (Again, this is assuming the Service from the Utility Transformer is sized to handle the full bus capacity.....)
Click to expand...

Yes, but need I say that's a high stakes assumption at this amperage? :cool:
 
DuvNJ said:
...assuming the Service from the Utility Transformer is sized to handle the full bus capacity...
Click to expand...
The service transformer and service conductors on the POCO side of the service point have no bearing on your restrictions. If all you have on the premises side is 3000A bus and a MCB, your service rating is the smaller of the bus rating or MCB trip setting.
 
jaggedben said:
230.40 Exception 5 specifically mentions 'one set of service conductors' for 'each or several' PV systems. So I guess that allows this. I agree with ggunn though. Consider which is easier.



Yes, but need I say that's a high stakes assumption at this amperage? :cool:
Click to expand...

Great feedback! Thank you....
 
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