Parallel Service Entrance Conductor Splice

[xguard]

I have parallel 500 MCM Service Entrance Conductors I want to splice into to supply a 100 AMP Service Disconnect.

I understand I need to splice into both sets and use a minimum of 1/0 conductors. If I bring these parallel 1/0 conductors to the service disconnect it looks like I will end up having to use a 400 AMP frame OCPD for wire bending space and lug size, where I only need 100 AMP based on the load.

Is it permissable to reduce the parallel 1/0 to a single 2 awg per phase prior to landing or terminating on the service disconnect?

 

[iwire]

How about purchasing Polaris type connectors with 5 ports?

2 incoming 500s, 2 outgoing 500s and one out going 3 AWG* to the 100 amp disconnect.


*You may have to bump that wire size up to match the listing of the connector.

 

[xguard]

I talked with a salesmen at Polaris. He said their connectors are used in that manner but did not sound confident that they were meant or listed to be used with parallel applicaitons.

 

[qcroanoke]

I have parallel 500 MCM Service Entrance Conductors I want to splice into to supply a 100 AMP Service Disconnect.

I understand I need to splice into both sets and use a minimum of 1/0 conductors. If I bring these parallel 1/0 conductors to the service disconnect it looks like I will end up having to use a 400 AMP frame OCPD for wire bending space and lug size, where I only need 100 AMP based on the load.

Is it permissable to reduce the parallel 1/0 to a single 2 awg per phase prior to landing or terminating on the service disconnect?

If they are service entrance conductors I'm pretty sure you can't tap them. But I am often wrong.
And after thinking about it I am.
What is on the load side of what they are feeding? That's where I would be looking.

 

[GoldDigger]

Are you saying that the only load on that set of service conductors is that 100A panel? That this panel is not a tap on a service that continues on elsewhere? Splice into implies a tap, but some of your other words seem inconsistent with that.

Is the double 500 for voltage drop or just because the service is larger than the building really needs? That may not affect the service termination but may affect the size of your GEC and bonding wires.

 

[iwire]

I talked with a salesmen at Polaris. He said their connectors are used in that manner but did not sound confident that they were meant or listed to be used with parallel applicaitons.

There is no requirement that they be listed for that specific purpose.

I have gone this route before when I had to split a 1200 amp feeder (3 sets of 600 CU) into 400 and 800 amp disconnects.

 

[xguard]

Are you saying that the only load on that set of service conductors is that 100A panel? That this panel is not a tap on a service that continues on elsewhere? Splice into implies a tap, but some of your other words seem inconsistent with that.

Is the double 500 for voltage drop or just because the service is larger than the building really needs? That may not affect the service termination but may affect the size of your GEC and bonding wires.

The parallel 500's currently supply an 800 A service disconnect. The 100 A service disconnect will be in addition to this 800 A service disconnect. I've done a load study and found that I have available capacity. I was avoiding using the word tap so I wouldn't imply that I thought it fell under the "feeder tap" rules.

 

[iwire]

If they are service entrance conductors I'm pretty sure you can't tap them.

As the OP mentions these are not feeder taps, they are just more service conductors.

We can have up to six, (even more sometimes) service disconnects and the OP seems to be adding one to an existing one.

As long as the load does not exceed the ratings of the conductors he is good to go.

 

[GoldDigger]

I would make sure, however, that the lower ampacity conductors connected to the higher ampacity service do not go very far, if at all, inside the building. Otherwise an inspector might take exception, justified or not.

 

[iwire]

I would make sure, however, that the lower ampacity conductors connected to the higher ampacity service do not go very far, if at all, inside the building. Otherwise an inspector might take exception, justified or not.

The disconnects have to be grouped anyway.

 

[hurk27]

I have parallel 500 MCM Service Entrance Conductors I want to splice into to supply a 100 AMP Service Disconnect.

I understand I need to splice into both sets and use a minimum of 1/0 conductors. If I bring these parallel 1/0 conductors to the service disconnect it looks like I will end up having to use a 400 AMP frame OCPD for wire bending space and lug size, where I only need 100 AMP based on the load.

Is it permissable to reduce the parallel 1/0 to a single 2 awg per phase prior to landing or terminating on the service disconnect?

Do not parallel a smaller set of conductors off the 500's as a loss or weak connection in one of the 500's will put half of the 800 amp services load through these smaller parallel conductors, your better off doing like Bob said and use the Polaris 5 port and bring a single 3awg to the 100 amp service, I have also seen crimp on lugs used with a bolt and nut and one smaller lug for the 3awg, as long as the parallel conductors are brought together at the point of the smaller tap there would be no problem, the Polaris tap will make the job much easier and last longer then using crimp lugs and a bolt, also like Bob pointed out, 230.72 will require all disconnects to be grouped.

I notice you said that you have a little extra room for the 100 amp load, I hope you used the 760 amps the parallel 500's are rated for instead of the 800 amp rating of the disconnect?

Lets say the 800 amp service has a 680 amp calculated load and you add a 90 amp calculated load with the 100 amp disco, you now have a problem with the 500's being to small, this is missed by quite a few.

 

[xguard]

Do not parallel a smaller set of conductors off the 500's as a loss or weak connection in one of the 500's will put half of the 800 amp services load through these smaller parallel conductors, your better off doing like Bob said and use the Polaris 5 port and bring a single 3awg to the 100 amp service, I have also seen crimp on lugs used with a bolt and nut and one smaller lug for the 3awg, as long as the parallel conductors are brought together at the point of the smaller tap there would be no problem, the Polaris tap will make the job much easier and last longer then using crimp lugs and a bolt, also like Bob pointed out, 230.72 will require all disconnects to be grouped.

I notice you said that you have a little extra room for the 100 amp load, I hope you used the 760 amps the parallel 500's are rated for instead of the 800 amp rating of the disconnect?

Lets say the 800 amp service has a 680 amp calculated load and you add a 90 amp calculated load with the 100 amp disco, you now have a problem with the 500's being to small, this is missed by quite a few.

I used the parallel 500 MCM 760 AMP Rating as my weakest link.

The existing connected load (including 1.25 for continuous loads ) is 599 Amps.

I allotted
66 Amps for connected load ( including 1.25 for continuous loads), and 25% Spare, to the new 100 amp panel (fed by the new 100 amp disconnect).

For a total of 665 AMPS.