Follow this if you can

[brian john]

Single set of 500 kcmil CU from 4000 amp main switchboard exceeding 25' to 400 amp fusible safety switch (FSS) fused at 400 amps.

Load of FSS is parallel 250 kcmil CU to trough

from trough parallel 350 kcmil Al to Normal connections in 600 amp ATS

Single set of 500 kcmil CU from load connections in ATS to trough where it is connected to single set of 4/0 CU.

The 4/0 goes to a line connections of a 400 amp FSS fused at 250 amps.

From here a single set of 350 kcmil AL go to a single elevator 61 amps FLA
additionally a single set of 350 kcmil AL goes 18 floors to a 400 amp MLO panel with elevator lighting loads and 2 - 61 FLA elevators and 4 - 49 FLA elevators.

And they wonder why the conduit is warm (HOT).

 

[mdshunk]

That sure is taking advantage of the tap rules. Check me out on this. I'm probably in the ballpark:

Single set of 500 kcmil CU from 4000 amp main switchboard exceeding 25' to 400 amp fusible safety switch (FSS) fused at 400 amps.

I'd call that good for 380 amps

Load of FSS is parallel 250 kcmil CU to trough

I'd call that good for 310 amps

from trough parallel 350 kcmil Al to Normal connections in 600 amp ATS

I'd call that good for 500 amps

Single set of 500 kcmil CU from load connections in ATS to trough where it is connected to single set of 4/0 CU.

I'd call that conductors good for 380 amps connected to conductors good for 230 amps

The 4/0 goes to a line connections of a 400 amp FSS fused at 250 amps.

Das nicht gud.

From here a single set of 350 kcmil AL go to a single elevator 61 amps FLA
additionally a single set of 350 kcmil AL goes 18 floors to a 400 amp MLO panel with elevator lighting loads and 2 - 61 FLA elevators and 4 - 49 FLA elevators.

I'd call those 250 amp conductors

And they wonder why the conduit is warm (HOT).

Wonder no more. Sounds like you have a lot of work you're recommending to be done, eh?

 

[RUWired]

Single set of 500 kcmil CU from 4000 amp main switchboard exceeding 25' to 400 amp fusible safety switch (FSS) fused at 400 amps.

The tap itself is a violation even if he kept it at 25'.One third of 4000 is 1320 amps.
Rick

 

[Pierre C Belarge]

Brian
I believe I have seen a similar installation like that before.

It is called:

A temporary heater auto-igniter system

Depending on the weather is whether or not how long the temporary heater will last before the auto-igniter will actually work. :wink:

 

[cadpoint]

For all you'll playing at home that the 10' foot tap rule with exception to 25' using 1/3 via/math ...

And yes I got lost ...

 

[don_resqcapt19]

The tap itself is a violation even if he kept it at 25'.One third of 4000 is 1320 amps.
Rick

No matter what the line side OCPD is (assuming it is greater than 380 amps) you cannot terminate a 500 kcmil tap conductor on a 400 amp OCPD. You are not permitted to use the "round-up" rule for tap conductors.

Edited to correct left out "not" in original post. Sorry for the confusion

 

[RUWired]

No matter what the line side OCPD is (assuming it is greater than 380 amps) you can terminate a 500 kcmil tap conductor on a 400 amp OCPD.

Don, you lost me. Did you mean 4000 amp ocpd. If yes, feeder taps require tap conductors to be 1/3 the line side ocpd.

 

[jim dungar]

Don, you lost me. Did you mean 4000 amp ocpd. If yes, feeder taps require tap conductors to be 1/3 the line side ocpd.

Only if the tap is longer than 10' and less than 25'.

 

[don_resqcapt19]

Don, you lost me. Did you mean 4000 amp ocpd. If yes, feeder taps require tap conductors to be 1/3 the line side ocpd.

I left out a word when I made my post ...It should have said no matter what you cannot use a 400 amp OCPD on the load end of a 500 kcmil tap conductor.

 

[iaov]

Brian
I believe I have seen a similar installation like that before.

It is called:

A temporary heater auto-igniter system

Depending on the weather is whether or not how long the temporary heater will last before the auto-igniter will actually work. :wink:

That is dandy Pierre!:grin: