Hello all, and first off thanks for the help in advance. I'm a maintenance engineer, but I'm basically illiterate when it comes to the electrical side of things. Hoping some of you folks here can help educate me, as this is a topic I'd like to learn more about.
We have a new machine that we're looking at bringing in within the next month or two. This is our system we're hoping to tie into.
Step 1) Utility 12470 coming in
Step 2) Transformer 12470 to 480
Step 3) Switchgear 480 3ph
Step 4) 400A Breaker
Step 5) Overhead bussbar
I've hooked up this to log what our amp draw is for each phase:
http://en-us.fluke.com/products/digital-multimeters/fluke-3000-fc-industrial-system-kit.html
My question is this, with a 400A breaker what are the equations to calculate the load to trip the breaker for the following:
1) Single phase load........400A?
2) Total load.....................
3) Imbalance...................
I know part of this will be specific to the breaker, I just want to understand the whole picture. Due to arc flash requirements, we can't remove the panels, so I'm having to hook the fluke kit up where the wire lugs onto the bussbar, since they are level 0 because of the breaker. Also, the switchgear is about 30 yrs old.
I'm also overlooking what the load is on the switchgear itself, at least for now, under the assumption that the same equations will apply, and that we can't measure it due to arc flash restrictions. I'm assuming that we want it to be below 80% capacity, right?
We have a new machine that we're looking at bringing in within the next month or two. This is our system we're hoping to tie into.
Step 1) Utility 12470 coming in
Step 2) Transformer 12470 to 480
Step 3) Switchgear 480 3ph
Step 4) 400A Breaker
Step 5) Overhead bussbar
I've hooked up this to log what our amp draw is for each phase:
http://en-us.fluke.com/products/digital-multimeters/fluke-3000-fc-industrial-system-kit.html
My question is this, with a 400A breaker what are the equations to calculate the load to trip the breaker for the following:
1) Single phase load........400A?
2) Total load.....................
3) Imbalance...................
I know part of this will be specific to the breaker, I just want to understand the whole picture. Due to arc flash requirements, we can't remove the panels, so I'm having to hook the fluke kit up where the wire lugs onto the bussbar, since they are level 0 because of the breaker. Also, the switchgear is about 30 yrs old.
I'm also overlooking what the load is on the switchgear itself, at least for now, under the assumption that the same equations will apply, and that we can't measure it due to arc flash restrictions. I'm assuming that we want it to be below 80% capacity, right?