Generator question
- Thread starter Outfield7
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Is this an optional stdby?? if so.
702.5 Capacity and Rating.
(A) Available Short-Circuit Current. Optional standby system equipment shall be suitable for the maximum available short-circuit current at its terminals.
(B) System Capacity. The calculations of load on the standby source shall be made in accordance with Article 220 or by another approved method.
(1) Manual Transfer Equipment. Where manual transfer equipment is used, an optional standby system shall have adequate capacity and rating for the supply of all equipment intended to be operated at one time. The user of the optional standby system shall be permitted to select the load connected to the system.
The AHJ may require a demand calc.
702.5 Capacity and Rating.
(A) Available Short-Circuit Current. Optional standby system equipment shall be suitable for the maximum available short-circuit current at its terminals.
(B) System Capacity. The calculations of load on the standby source shall be made in accordance with Article 220 or by another approved method.
(1) Manual Transfer Equipment. Where manual transfer equipment is used, an optional standby system shall have adequate capacity and rating for the supply of all equipment intended to be operated at one time. The user of the optional standby system shall be permitted to select the load connected to the system.
The AHJ may require a demand calc.
I would think that if you install the double throw switch ahead of the existing service disconnect then you would be required to separate the neutrals and grounds in the existing service per 250.24(A)(5) and relocate your grounding electrodes to the dt switch.
Pierre C Belarge
Senior Member
- Location
- Westchester County, New York
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
702.2(B)(1) last sentence:
you just can't do this on an automatic transfer switch.
the manual transfer switch either has to be service rated or have a disconnect with OCPD's ahead of it to the service, if the service already has a outside disconnect and you put the MTS between it and the panel, your good to go.
...as in replace the service disconnect with a service-entrance-rated manual transfer switch?
In this case, the GEC and main bonding jumper connections are located in the transfer switch.
The latter option is to simply interrupt the service disconnect's load side feeder, if available, with the manual transfer switch.
Hmmm.... I don't understand unless you put in a FUSED double throw switch.
IMO, he may as well just replace the service disconnect with a service-entrance-rated manual transfer switch... as that is essentially what he'd be doing, except as suggested he'd end up with an extra, non-essential disconnect.
...but from an economical standpoint, the best option is to interrupt post-disconnect if feasible.
Must it be fusible ???
250.24 states: (5) Load-Side Grounding Connections. A grounded conductor shall not be connected to normally non–current-carrying metal parts of equipment, to equipment grounding conductor(s), or be reconnected to ground on the load side of the service disconnecting means except as otherwise permitted in this article.
(emphasis added)
Is a service rated non-fuses DT switch a service disconnecting means ?
I would think we might get various opinions on this.
Mvillines
Senior Member
- Location
- Western KY on the Ohio River
I would say a non-fused DT switch is the service disconnecting means
provided you comply with section 230.91
Pierre C Belarge
Senior Member
- Location
- Westchester County, New York
At this point, what does "located immediately adjacent thereto" mean?
To me, it means it is part of or nippled to the enclosure with the overcurrent device. So, in a residential application (actually, any application where the persons are not properly trained), if there is a length of cable from the non-fused disconnect to the transfer switch, and then from the transfer switch to the original service, I would not accept it as an inspector - based on my experience and the wording I see in the above supplied section number. JMHO
Mvillines
Senior Member
- Location
- Western KY on the Ohio River
Pierre I agree. It?s my understanding that immediately adjacent thereto is just what it says. The overcurrent device (circuit breaker or fuses) must be adjacent to the non-fused transfer switch and not separated by a wall such as a meter base mounted outside and the overcurrent device located immediately inside. I would and have allowed installations where the conductors leaving a meter base, entering a non-fused transfer switch (service rated) then leaving the TR Switch and entering a panel with an OC device. TR switch and panel must be installed on the same wall surface (immediately adjacent thereto) and connected by a short nipple.
I'm getting a foggy picture of your comment.
I was of the impression augie was talking about putting a DT disonnect ahead of the [original?] service disconnect. The DT switch is the transfer switch... and due to its placement would be required to be service equipment rated. If there is no ocpd associated with the DT switch, as in integral or located immediately adjacent thereto, it would not be the service disconnect and thus relocation of the earth bonding would not be required. At this point I'm not even certain such would be compliant, but cannot think of any prohibition offhand. Regardless, I would never suggest such an installation. My preference is to just replace the service disconnect with a service-entrance-rated transfer switch, or a non-service-entrance-rated one somewhere "downstream".
As noted by others, ocp must be integral or located imediately adjacent thereto to qualify as a service disconnecting means. If you put a service-equipment-rated, non-fusible DT switch ahead of the existing service disconnecting means, nothing changes as far as the service disconnecting means. The DT switch enclosure, conduits, etc. would get bonded to the grounded conductor, or in the case of an ungrounded system would require an equipment bonding jumper.
Mvillines
Senior Member
- Location
- Western KY on the Ohio River
Installing a transfer switch ahead of the service disconnect would not be in complince of 230.82.
A non-fused service rated transfer switch (if installed ahead of the original service disconnect) would become the service disconnect and section 230.91 would apply.
A non-fused service rated transfer switch (if installed ahead of the original service disconnect) would become the service disconnect and section 230.91 would apply.
jonathan hickman
Member
generator
generator
In the code ware would i look to find that you can not run emt to the generator you must change it over to flex thanks
generator
In the code ware would i look to find that you can not run emt to the generator you must change it over to flex thanks
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Pierre C Belarge
Senior Member
- Location
- Westchester County, New York
I was not even thinking of the transfer switch, but the general prinical of the service overcurrent device located immediately adjacent thereto, of the service disconnect.
Good call Mvillines
Good call Mvillines
jonathan hickman
Member
generators
generators
I need to know wareto find in the code ware you must change over to flex from emt thanks
generators
I need to know wareto find in the code ware you must change over to flex from emt thanks
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I don't know that you will find that in the NEC. Changing to a flexible conduit would be dependent on the possibility of vibration. Other than manufacturers requirements this has always seemed like more of a common practice approach when needed.
bullheimer
Senior Member
- Location
- WA
sec's not allowed in emt unless outside the building. pvc ok tho. now don't confuse me with what's what in this hypothetical mess. and i can't say that flex would be permitted either. maybe somebody else will help you out. which way'd you come in? bye bye, nice visiting wit y'all.
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