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Friday, November 18, 2016
Question:
There is an Electrician doing work in a Classified area. He is installing a 200 Amp panel that is on a cart that is Movable, and he is using a floating ground, My question is that should he drive a ground rod at the different locations to make it safe, Where in the Code can I find the Answer? I enjoy your work, it makes me look in the code book regularly. To check your answers.
John Quick
A
Answer:
Hey John thanks for your question and the compliment, please keep checking the answers and send in a comment if you think something was missed.
I'm trying to visualize a panelboard, as defined in Article 100, mounted to a cart and understand why that would be needed so am wondering if you actually mean an industrial control panel as defined in 409.2. I'm also guessing that a flexible cord is being used to supply the equipment on the cart and that the flexible cord contains an equipment grounding conductor but am not sure what you mean by a floating ground. The flexible cord and the connection provisions need to comply with 400.7 and 501.140 (for a Class 1 Location).
Unless there is a separately derived system larger than 1 kVA that needs to be grounded as stated in 250.30 the equipment grounding conductor can be used to provide an effective fault current path for the equipment on the cart as stated in 250.138. NFPA 77 provides information on grounding and bonding to deal with static electricity if that is a concern.