4000A/1000A tap

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chris kennedy

chris kennedy

Senior Member
Location
Miami Fla.
Occupation
60 yr old tool twisting electrician
I need to tap off these.

View attachment 2176



These are ten 500 thw from POCO vault ahead of main. I'm adding three 600's to a new 1000A main.

I want to use three of these lugs (figure 4) on each buss.

First problem, removing existing single lugs leaves one mounting hole, new stack lug has 2.

Second, does anyone see a problem having a POCO feeder and a tap to new main in one stack?
 
mdshunk said:
Don't suppose there's any extra holes in the bus?
Click to expand...
No sir, and the only solid part of the buss is where the lugs are now.

I should add that this is FPE gear. Is there someone I can contact that could still make engineering calls on this? Besides my EE.
 
chris kennedy said:
IFirst problem, removing existing single lugs leaves one mounting hole, new stack lug has 2.
Click to expand...

Ask the lug manufacturer (thats who the gear manufacturer would call).
Many two hole lugs are for "anti-rotation" not for current carrying capability.
 
I agree with Dungar on the anti-rotation, also I recall the rule of thumb:
The surface area of the lug tab must be 2 and 1/2 times equal to or greater than the cross-sectional area of the lug tab with regard to current carrying capability.
 
Chris, I'm not sure if you can tap parallel conductors in the manner you are

discribing. I'm sure if you tapped the bus after the parallel connections it

would be fine. If you have a NECHandbook read commentary following 310.4

2005.

Basicly it says you have to tap all of the parallel conductors in each phase

to your new tap conductors or an imbalanced load on the parallel conductors

will result. I don't know if your plan fits this requirement, or if you even

thought about it.
 
benaround said:
Basicly it says you have to tap all of the parallel conductors in each phase

to your new tap conductors or an imbalanced load on the parallel conductors

will result. I don't know if your plan fits this requirement, or if you even

thought about it.
Click to expand...
Oh I thought about it. Thats why I asked about putting both in one stack. The other plan would be to move more POCO conductors to the stacks and have the tap conductors together on the end of the buss.

I need to call the EE that designed this.
 
32 Teams, 30 Lugs

32 Teams, 30 Lugs

Bump.

As your second guessing and critiqueing other peoples strategies today, could you take a moment to critique mine?:smile:

Thank you,
Go Fins:roll:
 
All right, Chris, I see your bump and raise you two camels. :)confused:)

Okay, here's my plan: Get pieces of the same bus material as are between the bars where the logs are, and push them between the bars where the spaces are.

Then, drill new holes through both the existing buses and the sections you fill in the gaps with, and mount your new taps there. That way, you contact them all.

How's that? :)
 
iwire said:
That is all I could come up with as well but in my area an inspector would likely want an EE to give that change a blessing.
Click to expand...
Might that exceed POCO limit of 10 sets of conductors?

I recall you mentioning something about the limit in another thread.
 
Bump

Bump

This will happen this Saturday. Please see this again. The question is would there be a problem in your opinion with landing POCO close to the buss with my tap to new service on the outside. Possible unbalance of the POCO conductors lugged with the tap?
 
So, You are going to use 1000a off the 4000a, I don't know how tight the

load is but, and this is out of the box, take 3 each phase conductors and

reland them in dist. blocks, add your 3 each phase conductors to the block.

That leaves 7 x 380a =2660 for the original load.

What happened to the ' double up ' the existing conductors and use the

freed up space for the new stuff. 600mcm alum.!!
 
chris kennedy said:
This will happen this Saturday. Please see this again. The question is would there be a problem in your opinion with landing POCO close to the buss with my tap to new service on the outside. Possible unbalance of the POCO conductors lugged with the tap?
Click to expand...

Chris,
What would be wrong with using the 4 hole lugs?
Sounds like an easy solution.
 
benaround said:
What happened to the ' double up ' the existing conductors and use the

freed up space for the new stuff. 600mcm alum.!!
Click to expand...
Thats still the plan, but I want to know the effect on the lug, lateral, and buss if I combine incoming current and outgoing current on a double stack. The more I think about it, the more I think it's fine.

I'm constantly surprised around here, tell me why this would be bad.
 
jrannis said:
Chris,
What would be wrong with using the 4 hole lugs?
Sounds like an easy solution.
Click to expand...
I'm not going to drill the buss. I need a lug that will fit in the existing space.

Here is a quick quiz. Without going Googling, how much would you guess a stack lug for two 600 costs?
 
chris kennedy said:
I'm not going to drill the buss. I need a lug that will fit in the existing space.

Here is a quick quiz. Without going Googling, how much would you guess a stack lug for two 600 costs?
Click to expand...
The GNP of Upper Volta!:grin:
 
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