Based on the latest information from the manufacturer we have gone ahead and pulled full size neutrals in the parallel feeders. Also as recommended by the manufacturer we have not bonded the neutral. Thanks everyone for your input. Very interesting reading.
Here is an explanation I received from one of the engineers that works for the manufacturer.
"These are circulating currents between the UPSs. They are not current being delivered to the load.
When paralleling UPSs, there are multiple inverters that are constantly adjusting their outputs to...
We are installing 2 - 3 phase UPS modules in parallel to a common SBM. The manufacturer of the UPS is requiring a neutral being pulled in each of 4 parallel feeders from the UPS to the SBM. This neutral will not be bonded and will carry no load as all loads are 3 phase 3 wire. This neutral is...
The question is not how to calculate voltage drop, I have a voltage drop calculator and I understand the formula for calculating it. I have an engineer of record who has miscalculated and an owner that won't allow a change without documentation to prove the engineer wrong. We have discussed this...
This question is in regard to how voltage drop is calclated for a circuit from a distribution panelboard. I know how the calculation is done and that it needs to be no more than 3%. My issue is an electrical engineer that does not understand how to calculate the voltage drop for a circuit. He...
If I was the electrical inspector I wouldn't pass it, that is one of my concerns. The cable has been modified from it's original form even though all the strands may be there.
Just seems like an all round bad idea. Part of my issue is I have a design team telling me this is what needs to be done...
In a transportation tunnel we are building we have installed a grounding grid under the concrete slab. Prior to pouring the concrete a waterproofing membrane was applied on top of the sub soil. The grounding conductor is stubbed up through the waterproofing membrane to be attached to the rail...
Thanks for the responses guys, these are the methods I have always used in the past, but just wanted a second or third opinion on the results. We have a local testing company promoting a new meter that they are the only ones in the area to possess, and they are saying this is the only way we can...
Thanks for the response trosepe. Would this also be true if the slope method had been used to perform this test? That is the case in this instance.
I don't know why you could not open the attachment, I tried and it opened right up.
We are testing a large ground grid, approximately 400 feet by 200 feet using the fall of potential slope method with the C2 electrode distance of 500 feet from the test point of the grid. Attached is the test report for the grounding system with noted results. We have been told this is not a...
whycliffrussel - While the cable is only three years old, the issue at hand is as follows: I will try to keep this as short as possible.
A customer of ours has 10 - 2 mW generators at 13.2 kV, one of these generators had a fault in the 15 kV cables leading to the PTs. These 3 - #14 15 kV cables...
I have heard differing opinions on whether or not to Hi-Pot test service aged medium voltage cable. What are the NETA standards in regard to this. These cables are approximately 3 years old at 13.2 kV.
