How about checking me on this

[oldsparky52]

The job is to replace 2 disconnects. The disconnect on the left is going from a 1,000-amp rating to a 1,200-amp rating. We are limited to using no greater than 500 kcmil conductors. The EE has it drawn up for 4 sets of 350kcmil.

So, it looks like it's going to be very difficult to get a 4th conduit installed between the disconnect on the left at the CT cabinet, and if we did, the conductors would most likely be different lengths and in this short of a run, that might be a high %.

I'm thinking about recommending a wireway be installed between the CT cabinet and new disconnect. Connect the wireway with either a 5" nipple or (2) 3.5" nipples (at each end). The reasoning is if we put more than 3 CCC's in a conduit we have to derate which kills our ampacity rating, but since there are less than 30 CCC's in that wireway, no derating would be required, and the connections at each end of the trough are short enough that derating would not be required (less than 24").

In order to determine the minimum dimensions of the wireway, I did the following:

350kcmil @ 0.5242 x 12 = 6.5583 sq in
3/0 @ 0.2679 x 1 = 0.2679 sq in

6.5583 + 0.2679 = 6.5583 sq in

6.5583 / 20% = 32.79 sq in

So a 6" x 6" wireway would suffice.

Did I miss something?

 

[RB1]

Your wireway calculations look OK. I am not sure how you came up with 3/0. Per 250.102(C)(1)(a) 350K X 4 = 1,400K X 12.5% = 175K = 4/0.

Although a 6 X 6 will work per code, I would go with a larger size for ease of installation

 

[oldsparky52]

Your wireway calculations look OK. I am not sure how you came up with 3/0. Per 250.102(C)(1)(a) 350K X 4 = 1,400K X 12.5% = 175K = 4/0.

Although a 6 X 6 will work per code, I would go with a larger size for ease of installation

The drawings are calling for the 3/0, I assumed they were using Table 250.66. I didn't even check it.

I agree with the 8 x 8 wireway (larger size).

Thanks for your response.

Edit: Now that I think about it, the installation was going to be all PVC conduit, so that bonding jumper was never called out. The CT cabinet would be bonded to a neutral conductor and the service disconnect would get the GEC. Thank you for pointing out that sizing issue.

 

[Ponchik]

curious: Do you have to satisfy the 110.26 requirement as part of your project?

 

[oldsparky52]

curious: Do you have to satisfy the 110.26 requirement as part of your project?

I've brought that up at least 4 times in the past 8 months. The marina manager finally told me to not be concerned about it. There are some very "connected" people involved, and as best as I can tell, they are of the opinion that they can do whatever they want. They got it passed before, and they believe they can do it again.

I am not pulling the permit, the marina's favorite son is doing it (and the job), and since he is mostly a resi contractor, they have hired me to babysit the electrical. I am pulling the permit and wiring the fuel system.

I'll try to remember to come back in a couple of months to let you know if the "Billionaire's Club" gets their way or have to follow the rules like the rest of us. Demo has started, and as far as I can tell, the only permit actually obtained is the CAMA permit. I think building has been applied for but not sure of the electrical. I just watch in amazement.

It's not a bad job for me, I get about 2.5% of the electrical project for pointing and talking. Probably a little cheap, but no liability (other than what I'm getting paid) and no physical work (other than the fuel electrical).

 

[chris1971]

I've brought that up at least 4 times in the past 8 months. The marina manager finally told me to not be concerned about it. There are some very "connected" people involved, and as best as I can tell, they are of the opinion that they can do whatever they want. They got it passed before, and they believe they can do it again.

I am not pulling the permit, the marina's favorite son is doing it (and the job), and since he is mostly a resi contractor, they have hired me to babysit the electrical. I am pulling the permit and wiring the fuel system.

I'll try to remember to come back in a couple of months to let you know if the "Billionaire's Club" gets their way or have to follow the rules like the rest of us. Demo has started, and as far as I can tell, the only permit actually obtained is the CAMA permit. I think building has been applied for but not sure of the electrical. I just watch in amazement.

It's not a bad job for me, I get about 2.5% of the electrical project for pointing and talking. Probably a little cheap, but no liability (other than what I'm getting paid) and no physical work (other than the fuel electrical).

If your name is on the check, you will have some of the Liablity even if didn't even pick up a tool.