Service Rated Transfer Sw. - No OCPD

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iwire said:
That certainly could include the TS and the immediately adjacent to it OCPD.
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Not sure I see their accessories as something external to the equipment however I may be wrong.

Also, they wired the panel with 4 wires so if those conductors are considered se conductors then they would need to make that panel a 3 wire - no egc. IMO that would be the best fix.
 
iwire said:
That certainly could include the TS and the immediately adjacent to it OCPD.
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I think that is exactly what the IAEI stated in the above post but clarified that the bonding must be in the service disconnect so it would need 4 wires to the panel--- my earlier suggestion would be incorrect
 
Dennis,

Unfortunately I was unable to open the IAEI response, but according the UL General Guide Information for Electrical Equipment transfer switches without integral overcurrent protection are permitted to be marked in one of three ways. Each method requires the manufacturer to indicate the maximum rating of fuse or circuit breaker permitted to protect the transfer switch. It is my understanding, from a UL representative, that unfused service-entrance-rated transfer switches are intended to be used as the disconnecting means required by 225.36 and 250.32(B) Exception No. 1.

RB
 
With the panel adjacent, I have no problem with the install.
I would consider the conductors between the TS and the panel as Service Conductors simply because they don't meet the definition of a "tap" per 240.2
 
augie47 said:
With the panel adjacent, I have no problem with the install.
I would consider the conductors between the TS and the panel as Service Conductors simply because they don't meet the definition of a "tap" per 240.2
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So if they are service conductors then the egc must be removed and bonding would need to be done in both panels. Sounds like a violation of 250.24(B) as the IAEI stated
 
RB1 said:
Dennis,

Unfortunately I was unable to open the IAEI response, but according the UL General Guide Information for Electrical Equipment transfer switches without integral overcurrent protection are permitted to be marked in one of three ways. Each method requires the manufacturer to indicate the maximum rating of fuse or circuit breaker permitted to protect the transfer switch. It is my understanding, from a UL representative, that unfused service-entrance-rated transfer switches are intended to be used as the disconnecting means required by 225.36 and 250.32(B) Exception No. 1.

RB
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I agree that the TS is the service disconnect but there needs to a service ocpd also. That is the key to this whole argument. Are the conductors feeders to the panel or are they service conductors? Then where does the bonding stop and if a feeder where is the ocpd required by 240.21
 
Dennis Alwon said:
So if they are service conductors then the egc must be removed and bonding would need to be done in both panels. Sounds like a violation of 250.24(B) as the IAEI stated
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As I read the IAEI response, both the TS and the panel are considered as service equipment.
Is there anything that prevents you from bonding two sections of service equipment.
We bond meters, CT cabinets and service disconnects all to the neutral or by jumpers on many jobs
 
When you read the response from IAEI they stated the bonding is to be done in the service disconnect. Also by definition the service conductors stop at the first disconnect. There are a lot of factors going on here that seem to contradict each other. It is not clear cut at all IMO. Now do I think there is a problem with the install as it is--- NO--- do I think it is compliant, not sure, but I tend to think not as written in the NEC
 
For those who could not read the pic from IAEI here is the wording

Can a transfer switch for a standby power system be located between the meter and a panelboard? Does the grounding electrode conductor and the main bonding need to be relocated to the transfer switch?

References 230.82. 230.91, 230.54

Answer 1) Yes, 2) Yes
Assuming no overcurrent protective device in the transfer switch then the double-throw transfer switch becomes the service disconnect. The main breaker in the panelboard becomes the service overcurrent protective device (NEC 230.91) that must be located adjacent to the switch. (switch outside, panel inside is not adjacent)

The switch and the panelboard still fall within the definition of service equipment. However NEC 250.24(B) requires the main bonding jumper to be located in the service disconnect enclosure. Very explicit to say service disconnect and not service equipment.
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Dennis Alwon said:
So if they are service conductors then the egc must be removed and bonding would need to be done in both panels. Sounds like a violation of 250.24(B) as the IAEI stated
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The main bonding jumper would be installed at the disconnect location only (the ats.)

There is no egc between the ats and the panel, there would be a "supply side bonding jumper." This would be required to bond both pieces of service equipment together.
 
david luchini said:
The main bonding jumper would be installed at the disconnect location only (the ats.)

There is no egc between the ats and the panel, there would be a "supply side bonding jumper." This would be required to bond both pieces of service equipment together.
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Firstly it is not an ATS just a TS--

The supply side bonding jumper seems to be in contrast to what the IAEI is saying since 250.24(B) states to bond only in the main disconnect. Now I agree that the way this should be done is to consider the panel and the TS to be service equipment and thus no equipment grounding conductor but the bonding must happen in both panels. Unfortunately that is not quite clear in all the sections that are pertinent in the NEC. The def. of service conductors for one stops at the service disconnect. I am assuming they did not follow thru for a situiation like this. I will propose a word change in def. to include service equipment unless someone sees an issue with this.
 
Something like replacing "service disconnect" with "the OCPD associated with the service disconnect", maybe?
Or just the minimal change of " disconnect " to "equipment"?
The former would give a precise point.
 
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Dennis Alwon said:
The supply side bonding jumper seems to be in contrast to what the IAEI is saying since 250.24(B) states to bond only in the main disconnect. Now I agree that the way this should be done is to consider the panel and the TS to be service equipment and thus no equipment grounding conductor but the bonding must happen in both panels. Unfortunately that is not quite clear in all the sections that are pertinent in the NEC. The def. of service conductors for one stops at the service disconnect. I am assuming they did not follow thru for a situiation like this. I will propose a word change in def. to include service equipment unless someone sees an issue with this.
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I think you are reading 250.24(B) incorrectly vis-a-vis the supply side bonding jumper.

240.24(B) says that the main bonding jumper should bond the grounded conductor to the service disconnecting means enclosure and the equipment grounding conductors. But there are no equipment grounding conductors originating in the disconnecting means enclosure, they are in the panel.

In the panel, the grounded conductor would not be bonded to the enclosure as it would create objectionable current.

But you still need to accomplish two things. First, you need to bond your service equipment together (your ts and your panel) per 250.92. Second, you need to get the egcs in the panel bonded to the grounded conductor and the disconnect enclosure. The supply side bonding jumper would accomplish both.

There is still only one grounded conductor bond (main bonding jumnper,) that is in the disconnect.
 
GoldDigger said:
Something like replacing "service disconnect" with "the OCPD associated with the service disconnect", maybe?
Or just the minimal change of " disconnect " to "equipment"?
The former would give a precise point.
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That is exactly what I did. Instead of service disconnect I proposed a change to service equipment. Did the same in 250.24(B) . BTW, the IAEI is the one who stated that 250.24(B) required the bonding in the disconnect not the service overcurrent protective device.

In your other post you mentioned equipment grounding conductor. IMO, there should not be an equipment grounding conductor run with those conductors because IMO they are service conductors. If they are feeders that opens up lots more issues especially with no overcurrent protective device at the source
 
I disagree with IAEI's interpretation. Transfer switches without integral overcurrent protection are required to be marked to indicate the rating of circuit breaker or fuse used to protect the equipment. Can that protection be provided on the load side of the switch? I don't think so. The service switch is permitted to be located ahead of the service overcurrent device by exception to 230.94; therefore, the switch is not protected by the service overcurrent device. The failure to protect the switch violates the listing of the equipment.

RB
 
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