Recent content by dougjl

I have a client that wishes to put a fence around a new 480V switch-gear that they are installing inside the plant. They want to do this to limit access to the equipment. I know that I need to meet the requirements of 110.26. My question is do I bond the fence to the building grounding system...

Thanks to all for the responses.

Thanks for that information. I am a bit confused about a shield wire. I have seen installations of higher voltages where the shield wire is located above the current carrying conductors, which makes sense in my mind for lighting protection etc. But, as I look around at the poles in the area...

Hi, I have a customer who has asked that a 13.8kV feed be fed overhead about a mile to a 13.8kv/4.16kV transformer. NESC says that a ground connection should be made to the neutral at the source. The issue is the switchgear that will be feeding this line is only 3W 3PH. Where do I get my...

Thank you for the information.

Hi, I have an installation where two sets of parallel 400 MCM conductors were installed in a cable tray. They were installed as individual conductors in a single layer. The voltage of the system is 480 three phase and the circuit is feeding from a switchgear to an MCC MLO main. An engineer at...

Thank all for your input. It has been very helpful.

There will be concrete footings that the frame will be bolted to. These footings will not have a vapor barrier beneath them, but the footings will only be a couple of feet deep. Since the steel will be bolted to the footing I am not seeing how this would be in contact with earth for 10' or more.

The new building will be 95,000 sq. ft. steel building. It will be serviced initially by one 2500 KVA 480V transformer. A second transformer may be added when more load is added to the production area.

Mike, It is not an option as NEC 250.50 requires that a metal underground water pipe be bonded to and used as a part of the grounding electrode system.

How big of a layer of embedded rebar are you talking? Just a 20' rod in a casing of at least 2" of concrete around it or more? I had considered this but wasn't sure how much rebar was enough for it to be effective. Thanks, Doug

If I am not mistaken, article 250 says a ground rod (supplemental grounding) is only "required" if there is a connection to incoming water pipe. In my case I have been told to expect that the incoming main will be plastic. I am putting the ground rods in regardless since it will be my only...

I have a site where a concrete foundation will be being poured for a new building. I had planned to connect to the re-bar with a bonding jumper in order to use the concrete as a grounding electrode. I have since found out that the foundation will be poured on a vapor barrier. My understanding...

NEC code 250.66 discusses the minimum sizing for the grounding electrode conductors. It shows that the largest size required as 3/0 when the area of the incoming service conductors exceed 1100 kcmil. 250.66(A) shows the minimum size for connecting ground rods, pipe & plates as 6 AWG...

Thank you very much for the information. Is anyone familiar with Austin Enclosures? One of my distributors has mentioned them, but again quality does matter and I am unfamiliar with their product line. thanks, Doug