Grounding/ bonding

[Nietz001]

Help,
Where in the code does it talk about reducing washers? Do they need a bonding bushing? Part 2 of my question, can you put a ground under a 1/4 20 nut and bolt? I thought it had to have threads
thanks jeff

 

[ryan_618]

The code talks about bonding in 250.96. According to the UL white book, reducing washers are considered acceptable for grounding and bonding. With that said, if the washers you are using are listed by UL, you would not need to bond around them.

 

[bphgravity]

Here is the statement from UL QCRV.GuideInfo:

Metal reducing washers are considered suitable for grounding for use in circuits over and under 250 V and where installed in accordance with ANSI/NFPA 70, "National Electrical Code."

 

[dlhoule]

I'd still recommend bonding around them. Doesn't 1/2 - 20 nut and bolt both have threads? What size ground are we talking about? We frequently use compression type terminal on up to #10 wire under 1/4 - 20.