10 seconds for LS power

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mshields

mshields

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Boston, MA
Had a meeting with a client yesterday who's asking me to bring life safety lighting circuits to a panel which is backed up by turbines that need as much as 30 seconds to get running. I told him that we should have battery packs for the interim which he scoffed at stating that Article 700 has wording allowing you to take more than 10 seconds if you have such a situation.

I think he's dead wrong. 700(12)(5) says that you may use such a genererator if you have an auxiliary power supply for the interim - like a UPS.

Before I tactfully breach this subject with my client, I'd like to be sure I'm not missing anything.

What do you say?

thanks,

Mike
 
MCP's vs thermal mag CB's

MCP's vs thermal mag CB's

This is the second of two messages I'm posting today looking for a sanity check on something a client of mine is telling me to do which I'm not comfortable with.

This one regards the use of MCP's in an MCC but on motor circuits where the feeder at the MCC is protected only by a breaker. He wants to use an MCC to take advantage of it's drawout capabilities even though all of the motor starters are remote near the motors. This I have no objection to, but he wants to save a few bucks and provide MCP's. He told me you could do this because of the tap rule. But all of our motors are more than 25 feet away. I say you need thermal mags at the MCC under this circumstance.

What say you?

thanks,

Mike
 
mshields said:
Had a meeting with a client yesterday who's asking me to bring life safety lighting circuits to a panel which is backed up by turbines that need as much as 30 seconds to get running. I told him that we should have battery packs for the interim which he scoffed at stating that Article 700 has wording allowing you to take more than 10 seconds if you have such a situation.

I think he's dead wrong. 700(12)(5) says that you may use such a genererator if you have an auxiliary power supply for the interim - like a UPS.

Before I tactfully breach this subject with my client, I'd like to be sure I'm not missing anything.

What do you say?

thanks,

Mike
Click to expand...

I think your understanding is correct.
 
mshields said:
This is the second of two messages I'm posting today looking for a sanity check on something a client of mine is telling me to do which I'm not comfortable with.

This one regards the use of MCP's in an MCC but on motor circuits where the feeder at the MCC is protected only by a breaker. He wants to use an MCC to take advantage of it's drawout capabilities even though all of the motor starters are remote near the motors. This I have no objection to, but he wants to save a few bucks and provide MCP's. He told me you could do this because of the tap rule. But all of our motors are more than 25 feet away. I say you need thermal mags at the MCC under this circumstance.

What say you?

thanks,

Mike
Click to expand...

Don is correct. If he wants to save money, how about fused switches in the MCC?
 
Thanks

Thanks

I'm not inclinded to take up the additional space that fusible switches would require. But it's a good point.

Mike
 
Turbine?!?!?

Turbine?!?!?

mshields said:
...scoffed at stating that Article 700 has wording allowing you to take more than 10 seconds if you have such a situation.
Click to expand...
Only if the AHJ approves of the turbine as the prime mover for the emergency system would be the only way around the ride through power supply. Don't hold your breath on anyone in that position to go against code.

I too read 700 like you do.

PS
Why a turbine?? Those things are expensive, don't like to be started and stopped and not just anyone can maintain them. If it is used for distributed generation, I'm not sure you can consider it a legally required standby system for LS loads....

Did he find one on EBAY? :)
 
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