Interconnected power supply

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Fcarr

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We are installing an outoodr micro turbine in an areaway that has access doors into the basement. The main electrical room is about 75-feet from the areaway. We are planning to install the main disconnect switch and other controls for the micro turbine within 25-feet of the main switchboard, just outside the electrical room because there is not space in the electrical room. We are also planning to install an non-fused disconnect switch outdoors in the areaway within sight of the micro turbine. The owner is asked that we not install two sets of disconnect switches. We believe they are needed at both locations. Can either disconnect switch be elimiated?
 
Does the microturbine have an output breaker ? If so, what do you see as the purpose of the non-fused safety switch at the turbine ? I'm not sure that it would be required. How are you interfacing the turbine with the utility supply ?

Just curious, but is this a Capstone unit ? I've installed several of them and just wondered.
 
Fcarr said:
We are also planning to install an non-fused disconnect switch outdoors in the areaway within sight of the micro turbine.
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What is this one for?

One switch at the building, to disconnect the building from the turbine would comply with 690.14(C)(1).

See also 690.14(C)(5).
A photovoltaic disconnecting means shall not be required at the photovoltaic module or array location.
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Disclaimer: Never done one of these.
 
The micro turbine does not have an integral breaker. An electrical grid protection package connects to the load side of the fused disconnect and the micro turbine has a main contactor wired to the grid protection package.
We believe the disconnect is required within sight of the micro turbine for service. NEC 705.22 identifies disconnect requirements. We are questioning the need for an additional disconnect at the micro turbine.
 
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georgestolz said:
What is this one for?

One switch at the building, to disconnect the building from the turbine would comply with 690.14(C)(1).

See also 690.14(C)(5).


Disclaimer: Never done one of these.
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why would a microturbine have to comply with a section dealing with photovoltaic systems?
 
petersonra said:
why would a microturbine have to comply with a section dealing with photovoltaic systems?
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IMO, it wouldn't. It would fall under 445. At least, that's the article we used when we installed a couple of them a while back. The AHJ agreed, BTW.

I'm not sure the microturbine thing has really caught on like the manufacturers thought (hoped?) it would. Rising natural gas prices impacted that, no doubt. If it ever does, look for a Code making panel to pick it up in an article.
 
I agree with Brad. 445 is what applies here. Wether it's a diesel-generator or a microturbine-generator, it's still a generator. 115% FLA and it doesn't have to be within sight.

JMHO
 
Pierre C Belarge said:
Why does the disconnect not have to be insight?
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I just read through 445 and 705, I didn't see a requirement for the disconnect to be on the equipment or within sight. That seems odd, though.

Edit: not to be in a totally different position than my original reply or anything... :D
 
If you read 445.18, it would seem to indicate that the generator has to be supplied with a disconnecting means.

445.18 Disconnecting Means Required for Generators.
Generators shall be equipped with a disconnect by means of which the generator and all protective devices and control apparatus are able to be disconnected entirely from the circuits supplied by the generator except where:
(1) The driving means for the generator can be readily shut down; and
(2) The generator is not arranged to operate in parallel with another generator or other source of voltage.

All of the microtubines I have ever seen all have a "kill" switch that I believe would comply with this requirement. Also, a natural gas turbine would have a gas valve to shut off the fuel supply.
 
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