AskCodeMan

Trying to interpret 1910.334(a)(3)(i)

"A flexible cord used with grounding type equipment shall contain an equipment grounding conductor."

I have a test bench that came with a built in "power strip" which is grounded to the bench, the bench is plugged into the wall outlet (3 prong), which has a ground (internal to the cable) that runs back to the breaker panel.

If I plug a device that only has 2 prongs into the "power strip" on the bench am I violating the above regulation. Or if the 2 prong connector on the flex cord has or doesn't have polarizing prongs does this make a difference?

What I'm looking for is an explanation like this; "if your test bench is grounded (by an individual grounding conductor) any device connected to it needs to be grounded meaning it must have a GND pin (3 prong) in the connector found at the end of the flex cord of the device." to comply with 1910.334(a)(3)(i)

or would 1910.302(b)(1) Requirements applicable to all installations. apply here?

Thanks

JohnSTI wrote:Trying to interpret 1910.334(a)(3)(i)

"A flexible cord used with grounding type equipment shall contain an equipment grounding conductor."

This is the key to that "used with grounding type equipment" ... equipment, appliances, tools, etc, which are listed and factory supplied with a two-wire cord and two-prong plug are not "grounding type equipment" as they have been tested and listed as being 'nongrounding equipment' (the original term was 'double insulated' equipment).

However, if you have equipment which came with a a three-wire cord and three-prong grounding-type plug, if the ground prong has been cut off, that equipment was, and still is, "grounding type equipment" and is required to be grounded. The use of a "grounding adapter" which you plug a three-wire three-prong grounding-type plug into and the adapter only has two prongs with a metal tab sticking out of it, that metal tab is supposed to be "grounded" before that "grounding type equipment" is used.

All too often those adapters were plugged into two-prong nongrounding-type receptacles and the ground tab was not grounded. That grounding tab is located where it is, and has a hole through it, for a reason - the cover plate screw is supposed to be placed through that hole and 'ground' the adapter's ground to the receptacle strap (which was presumed to be grounded, but more likely than not, the receptacle strap was not grounded and the adapter has no ground for its ground to be grounded to ... meaning that the adapter should not be used in those cases (i.e., should not be used in most of the uses it is used for).

But I digress ... and went off on a tangent ... this is the key: "used with grounding type equipment".

If the equipment is designed to be grounded, it needs to be grounded as it is "grounding-type equipment".

If the equipment originally came with a two-wire cord with a two-prong plug and was not designed to be grounded, it does not need to be grounded as it is not "grounding-type equipment".

Thanks Jerry that clears things up greatly...