Main bonding jumper

[hhsting]

I have 11 sets of 750kcmil Al conductors going into 3000A main service switchboard.

11x750=8250 kcmil

8250x0.125=1031.25 kcmil


The plans the main bonding jumper of 2 sets of 600kcmil Al which would yield 1200kcmil Al total since they are in parallel

So whats the problem?

I thought the main bonding jumper need to be unspliced according to 250.24(B). Does anyone know you can do sets of main bonding jumper in parallel or not? Am I missing something? Its going to be wire not manufacturer provided bus or other manufacturer provided items I already inquired with designer

 

[don_resqcapt19]

The code does not specify either way.
I do not see how parallel conductors equal a splice.
I see no issue with the parallel conductors, but if you do, mark the drawing up and send them back to the engineer.

 

[infinity]

I've never seen a 3000 amp servcie switchboard without a factory installed piece of bus serving as the MBJ.

 

[augie47]

I've never seen a 3000 amp servcie switchboard without a factory installed piece of bus serving as the MBJ.

agree. If it does not have a factory MBJ I would be suspect that it's not listed as service equipment

 

[hhsting]

The code does not specify either way.
I do not see how parallel conductors equal a splice.
I see no issue with the parallel conductors, but if you do, mark the drawing up and send them back to the engineer.

Engineer is the on who has shown 2 sets of 600kcmil AL. Engineer says they dont provide bus as MBJ

Curious how do you not see parallel sets of MBJ not a splice? They do have to connect together at ends how are they not splice?

 

[jaggedben]

It's two conductors terminated at each end. A termination is not a splice.

But I agree with the others. I've never seen any labeled as suitable for use as service equipment without a factory provision for the MBJ. At least, nothing under 30 years old. Is this new equipment?

 

[roger]

Engineer says they dont provide bus as MBJ

If the engineer has worked with you before he is probably just having fun with you knowing you would believe him.

Roger

 

[infinity]

Engineer is the on who has shown 2 sets of 600kcmil AL. Engineer says they dont provide bus as MBJ

Curious how do you not see parallel sets of MBJ not a splice? They do have to connect together at ends how are they not splice?

Get out the red marker, cross out the two sets of 600's and add a note that the MBJ must be a bus bar equivalent to 1031 CM and send it back.

 

[Tulsa Electrician]

Since it (MBJ) is not supplied. Is the equipment service rated?
I just assumed it was since your installing an MBJ and stated main service switchboard.

 

[Tulsa Electrician]

Also wondering if there's a neutral link disconnect. Which would be required.

 

[don_resqcapt19]

Engineer is the on who has shown 2 sets of 600kcmil AL. Engineer says they dont provide bus as MBJ

Curious how do you not see parallel sets of MBJ not a splice? They do have to connect together at ends how are they not splice?

A splice is a connection that extends the length of a single conductor, making it one longer conductor. A splice is between the two ends of a conductor. A set of parallel conductors cannot in any way be construed as being a splice.