generator connection

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Starbuc

Starbuc
Location
Lake City, FL
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Master Electrician
I know this topic has been hashed out alot allready but can someone give me the specific code that applies to having a service disconnect/protction device on the utility feed ahead of the transfer switch or a service entrance rated transfer switch. I have installed several generators and have allways added a fused disconnect if there wasn't one, and recently lost a bid to someone who isn't using one.

[ September 14, 2005, 01:01 PM: Message edited by: Lyn Rainbolt ]
 
Re: generator connection

Originally posted by Lyn Rainbolt:
I know this topic has been hashed out alot allready but can someone give me the specific code that applies to having a fused service disconnect ahead of the transfer switch or a service rated transfer switch. I have installed several generators and have allways added a fused disconnect if there wasn't one, and recently lost a bid to someone who isn't using one.
Click to expand...
2005 Cycle
445.18 Disconnecting Means Required for Generators.
Generators shall be equipped with disconnect(s) 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 both of the following conditions apply:
(1) The driving means for the generator can be readily shut down.
(2) The generator is not arranged to operate in parallel with another generator or other source of voltage.
Click to expand...
Could this be what you are looking for?
:)
 
Re: generator connection

I would think 99.99% percent of gen sets would qualify for exception 1 to 445.18 that was posted. IMO If you have a service entrance xfer sw, and main line ocpd at the gen set, you don't need a separate disconnect sw.
 
Re: generator connection

1999 445-10. 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.
Click to expand...
2002 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.
Click to expand...
2005 445.18 Disconnecting Means Required for Generators.
Generators shall be equipped with disconnect(s) 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 both of the following conditions apply:
(1) The driving means for the generator can be readily shut down.
(2) The generator is not arranged to operate in parallel with another generator or other source of voltage.
Click to expand...
I do not see exception 1 to this rule could you elaborate? What I do see is in 2005 the words where both was added. I do believe that it was always the intent that both apply.
:)
 
Re: generator connection

What's all the fuss about?

I have never seen a generator arrive on a job without a factory installed disconnecting means.
 
Re: generator connection

Originally posted by Lyn Rainbolt:
I have installed several generators and have always added a fused disconnect if there wasn't one, and recently lost a bid to someone who isn't using one.
Click to expand...
If there was a factory installed breaker on the generator you definitely do not have to add fuses at the generator. (Assuming the generator is not over sized for the conductors or transfer switch rating.)

The breaker can also meet the the requirements of 450.18.
 
Re: generator connection

I was not talking about load connected to the genset, I was asking about the service disconnect after the utility feed before the transfer switch.
 
Re: generator connection

The only disconnect that I am aware of before the transfer switch is the one outlined in 445.18.
If there is more than this required I am not familiar with it.
:)
 
Re: generator connection

I think we are missing the question. I know I am. Lyn wants to know if a disconnect is required on the line side of the transfer switch if it is not service rated.

Lyn, 230.70 requires a means to disconnect the service entrance conductors. 230.70(C) requires the service disconnect to be suitable for use as a service disconnecting means.

I agree with you that the transfer switch either needs to be service rated or you must add a service rated disconnect upstream of the transfer switch.

Sorry for the misread of your original post
 
Re: generator connection

Don't forget about the location of the Generator. If not in sight of, or more than 0 feet from the building, a disconnect at the building would also be required.

See 700.12(B)(6), 701.11(B)(5) & 702.11
 
Re: generator connection

I agree. If for instance, you had unfused service entance conductors under the six disconnect rule allowed in 230.90, and you wanted to add a transfer switch to serve the entire service, you would then need a main OCPD on the service entrance conductors in either the form of a fused disconnect in the case of a non-service entrance rated switch; or an integral utility MCB which would be included in the design of a service entrance rated transfer switch.
 
Re: generator connection

Lyn-If the transfer switch is service rated (per 230.66), you would not be required to have a fused disconnect ahead of it, nor would the transfer switch require integral overcurrent protection as long as your service overcurrent device was located immediately adjacent to the transfer switch per 230.91. For example, the utility meter nipples into the transfer switch and the transfer switch nipples into the panel. This panel is now a feeder panel and all grounding and bonding would be done in the transfer switch and an equipment grounding conductor would be run from the transfer switch with the feeder to the panel.

Of course, if your transfer switch is not service rated, then a service disconnect with overcurrent protection would need to be placed ahead of it.
 
Re: generator connection

Originally posted by sceepe:
I think we are missing the question. I know I am. Lyn wants to know if a disconnect is required on the line side of the transfer switch if it is not service rated.
Click to expand...
Yeah I should have read lyns post more carefully. :eek:

IMO the easy short answer is this.

The first equipment that the service conductors terminate in must be service rated.

If you have a service rated transfer switch you may not need a fused disconnect depending on the transfer switch having integral OCP.

If the transfer switch is not service rated it can not go on the line side of the service disconnect. (230.82)
 
Re: generator connection

question---can you go from load side of meter to main disc./brkr, then to "normal power" side of non service rated transfer switch.....then load from transfer swich passes thru disc. and into house via riser and LB?
 
Re: generator connection

I've never seen a SE rated transfer switch that did not have a utility disconnect. That's how they get to be rated SE. So, if you use a SE rated switch, no worries. If not, see the posts above.

Yes, you could hit the main disc. then a transfer switch and then feed the load(s). Keeping mind, of course, any tap rules and OCP required for the feeder(s).
 
Re: generator connection

I've never seen a SE rated transfer switch that did not have a utility disconnect...Sq D makes one.
Just be aware of the AIC rating required, the transfer switch without disconnect may not have adequate AIC rating.
 
Re: generator connection

Well, shut my mouth. Did not know that. We use ASCO and Zenith, so haven't had any exposure to the Sq D stuff.

Thanks
 
Re: generator connection

Originally posted by lbernier:
question---can you go from load side of meter to main disc./brkr, then to "normal power" side of non service rated transfer switch.....then load from transfer swich passes thru disc. and into house via riser and LB?
Click to expand...
Yes, that's exactly what is being described above for a non-service-rated transfer switch.
 
Re: generator connection

Originally posted by tom baker:
I've never seen a SE rated transfer switch that did not have a utility disconnect...Sq D makes one.
Just be aware of the AIC rating required, the transfer switch without disconnect may not have adequate AIC rating.
Click to expand...
I am confused now.

What possible use would a SE rated transfer switch be without a utility disconect?

You can not a install a transfer switch on the supply side of a service disconect. 230.82

The only way to have the transfer switch be the first piece of equipment from the service point is if it includes the service disconnecting means.
 
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