generator install

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how is it a code violation if the feeders are protected properly? i have installe many 25 kw gen sets on 200 amp panels. the service disconnect and transfer switch must of course match the 200 amp panel because in the utility postion the transfer switch carries the full panel load. in the emergency postion however typically a 25 kw gen set can only provide 86 amps or so and is protected by a 100 amp breaker. there is no code violation here as the generator and the feeders are properly protected. If the homeowner is not careful and adds too much load the ocp device will trip when it should and everything is protected. Where do you feel the code violation exists? design flaw maybe but code violation not methinks.
 
stew said:
how is it a code violation if the feeders are protected properly? i have installe many 25 kw gen sets on 200 amp panels. the service disconnect and transfer switch must of course match the 200 amp panel because in the utility postion the transfer switch carries the full panel load. in the emergency postion however typically a 25 kw gen set can only provide 86 amps or so and is protected by a 100 amp breaker. there is no code violation here as the generator and the feeders are properly protected. If the homeowner is not careful and adds too much load the ocp device will trip when it should and everything is protected. Where do you feel the code violation exists? design flaw maybe but code violation not methinks.
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The code violation is article 220. Your not allowed to overload a feeder or a branch circuit.. In the 2008 code they make it VERY clear that the generator must be sized for the load... Take a look at this article...

http://www.ecmag.com/index.cfm?fa=article&articleID=8401
 
interesting article. glad we arent on the 08 as yet. this will turn the automatic transfer switch and generator people on thier ears. It has in the past always been acceptable practice to do as I have state d earlier 220 or not. Never had an auto transfer for a 200 panel turned down. I s this another industry driven code change? seems it is. oh well i guess we have to have a load calc that matches the gen set or use 50 kw generators eh? what do you suppose the load calc is for an all gas 4500 square ft house? bet its not much more than 25 kw.if at all. guess ill have to do some theroetical calcs just to see.
 
Thom,
By design, within a meter can, there is already service and non-service rated conductors, depending on design. The point of contention seems to be the location of OCP, and mixing them after that,
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All of the conductors in a meter can for a normal service are service conductors and stay such until you get to the load side of the service disconnect. The code rule that is being cited, 230.7, only uses the word raceway and does not include other things that are being used as a raceway. Maybe another code proposal is needed here.
Don
 
don_resqcapt19 said:
A meter can is not a raceway even when used as such and therefore 230.7 does not apply. That section only applies to raceways and cables.
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stew said:
One of our electricians is installing a generac generator with a 200 amp service rated trnasfer switch. The service disconnect is incorporated as part of the transfer switch assembly. He intercepted the service wire from the meter and went to the transfer swith disconnect. good so far but then he nippled back to the meter can and sent the conductors from the transfer switch load side to the panel via the meter can and back thru the existing nipple to the panel. My contention is that the conductors after the service disconnect from the transfer swith are now feeders and not service conductors and should not occupy the same raceway(meter can used now as raceway). Am I correct and should another raceway be provided? my sense says yes.
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"sent the conductors from the transfer switch load side to the panel via the meter can and back thru the existing nipple to the panel."

Aren't we picturing mixing in the conduit ?

don_resqcapt19 said:
That wording even brings up more questions. If there are other conductors in the raceway, is it still a service raceway:D
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I hope you're not serious.

David
 
picture the conductors from the meter in a nipple going out to the transfer switch ,from the transfer switch back thru another nipplle back to the meter can and then th.ru the back nipple to the panel. so the conductors dont go thru any conduit together but are in the meter can together. The load conductors are now feeders and not service conductors and the can becomes the raceway for both.
 
don_resqcapt19 said:
Thom,

All of the conductors in a meter can for a normal service are service conductors and stay such until you get to the load side of the service disconnect. The code rule that is being cited, 230.7, only uses the word raceway and does not include other things that are being used as a raceway. Maybe another code proposal is needed here.
Don
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I agree (sometimes I type as I am thinking, and well...:grin: ). The curious aspect is that if you consider the ATS being described, service conductors and feeders are in the same enclosure, by design, with UL approval. I have passed many inspections with this very same layout and never considered it to be a violation until questioned by an inspector one day. Only a new proposal would clear it up. What a minute, that one deserves at least two :grin:s.
 
stew said:
picture the conductors from the meter in a nipple going out to the transfer switch ,from the transfer switch back thru another nipplle back to the meter can and then th.ru the back nipple to the panel. so the conductors dont go thru any conduit together but are in the meter can together. The load conductors are now feeders and not service conductors and the can becomes the raceway for both.
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Same raceway [conduit or tough without a barrier], then you have a problem with 230.7.
Same enclosure, I don't see a violation. . But as brought out before, check with the utility about mixing of metered and unmetered.

David
 
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