Polaris Taps in MDP

[rugger8008]

Mike this is Bryan Schultz with C. Davis Electric. Ed Davis wanted me to send you a message about an issue that come up today with an inspector. It is regarding polaris taps in an MDP. We have a 600 amp 600v breaker with 4 sets of 350 mcm. We had to polaris tap these 4 sets with 2 sets of 350 to land on the breaker. The inspector says we can not install it that and must install a non-fusable disconnect. He sighted 310.10(H)(2)

 

[david luchini]

I don't see anything in 310.10(H)(2) that would prohibit that.

 

[rugger8008]

So what can I tell the inspector?

 

[tom baker]

Mike hosts the forum, but very seldom answers. We have a very knowledgeable group that answers.
I dont quite follow your post, is this a ten foot feeder tap, does it end in a single OCPD?
Did you tap all the sets of 350s?
A one line would help

 

[rugger8008]

the tap is maybe 2' form the breaker to the polaris taps

 

[petersonra]

Mike this is Bryan Schultz with C. Davis Electric. Ed Davis wanted me to send you a message about an issue that come up today with an inspector. It is regarding polaris taps in an MDP. We have a 600 amp 600v breaker with 4 sets of 350 mcm. We had to polaris tap these 4 sets with 2 sets of 350 to land on the breaker. The inspector says we can not install it that and must install a non-fusable disconnect. He sighted 310.10(H)(2)

I would want to see a sketch of what you actually did before I was to comment.

I don't quite understand the 4 sets of 350 MCM thing.

 

[rugger8008]

Plans called for 4 sets of 350 mcm due to the length of the run. 4 sets of the 350 mcm will not fit on a 600 amp breaker. we used polaris taps and took 2 sets of 350 mcm to the breaker. the taps are 2' from the breaker.

 

[dkidd]

Mike this is Bryan Schultz with C. Davis Electric. Ed Davis wanted me to send you a message about an issue that come up today with an inspector. It is regarding polaris taps in an MDP. We have a 600 amp 600v breaker with 4 sets of 350 mcm. We had to polaris tap these 4 sets with 2 sets of 350 to land on the breaker. The inspector says we can not install it that and must install a non-fusable disconnect. He sighted 310.10(H)(2)

You should be able to do it if you have 6 hole units, 4 in and 2 out for each set of phase conductors.

 

[rugger8008]

We have a 6-barrel polaris tap and that is exactly what we did. 4 out to the panel and 2 to the breaker

 

[don_resqcapt19]

There is no tap here. The parallel 350's to the breaker have an ampacity of 620 amps. I see no issue with any of the rules in 310.10(H).

 

[augie47]

I agree with David (post #2) there is nothing in 310 that prohibits that,


(and don)

 

[rugger8008]

i wish the inspector saw it the same way. He is insisting we need to use a non-fusible disconnect instead of the taps in the MDP

 

[david luchini]

i wish the inspector saw it the same way. He is insisting we need to use a non-fusible disconnect instead of the taps in the MDP

I would suggest that the inspector doesn't understand that the two sets of 350mcm and the four sets of 350mcm are Separate Sets of parallel conductors. The requirements of 310.10(H)(2) apply to each set independently.

 

[petersonra]

i wish the inspector saw it the same way. He is insisting we need to use a non-fusible disconnect instead of the taps in the MDP

where is there a requirement for a NF disconnect in the code?

if the feeder originates in another building he may well be right that a disconnect is needed.

 

[texie]

i wish the inspector saw it the same way. He is insisting we need to use a non-fusible disconnect instead of the taps in the MDP

Your description indicates that you have met 310.10(H)(2). A non fusible switch obviously has no relation to the price of rice. The inspector is not competent and should be challenged on this as he is obviously wrong. That said, one thing might be an issue is do you have code compliant room for these Polaris taps? I would normally do something like this in a separate J Box near the breaker.

 

[Dennis Alwon]

From what I see is you have parallel service conductor being reduced from 4 sets to 2 sets. As long as the characteristics are the same on the run (before the tap to after the tap) there should not be an issue.

Ask the inspector to join us and read the forum... I would also go above the inspectors head if need be.

 

[Greentagger]

Code wise compliant. If you are working off engineered plans, what do the plans call for?

 

[infinity]

If you used a 4 port Polaris could you feed through just 2 of the 4-350's?

 

[texie]

If you used a 4 port Polaris could you feed through just 2 of the 4-350's?

Ha-ha. I suppose one could argue that would not be completely symmetrical but I don't think as a practical matter it would make any real difference.