Terminology

robert_duncan · Mar 29, 2014

What is the difference between a protective and operating ground as refer to in the 2011 NEC 810.51(I) ?

LEO2854 · Mar 29, 2014

robert_duncan said:
What is the difference between a protective and operating ground as refer to in the 2011 NEC 810.51(I) ?

Hello Robert welcome to the forum.:thumbsup:

Do you mean 810.21 (I)..?

Smart $ · Mar 30, 2014

robert_duncan said:
What is the difference between a protective and operating ground as refer to in the 2011 NEC 810.51(I) ?

Best guess...

Electrical ground is protective.

Transmission ground is operating.

K8MHZ · Mar 30, 2014

LEO2854 said:
Hello Robert welcome to the forum.:thumbsup:

Do you mean 810.21 (I)..?

In the 2008 it is mentioned in 810.58 B and C.

I just did a class on radio bonding and grounding. I take it to mean that the protective conductors are the grounding conductors that connect the antenna ground to the grounding electrode system and the operating conductors are the conductors that connect the equipment to the grounding electrode system.

Neither are defined by the NEC. If my interpretation is different (after being an amateur radio operator for 20 years come July) and can be proven incorrect I would like to know about that.

Smart $ · Mar 30, 2014

K8MHZ said:
In the 2008 it is mentioned in 810.58 B and C.

I just did a class on radio bonding and grounding. I take it to mean that the protective conductors are the grounding conductors that connect the antenna ground to the grounding electrode system and the operating conductors are the conductors that connect the equipment to the grounding electrode system.

Neither are defined by the NEC. If my interpretation is different (after being an amateur radio operator for 20 years come July) and can be proven incorrect I would like to know about that.

I believe you are correct. I had it backwards.

robert_duncan · Mar 30, 2014

Terminology

LEO2854 said:
Hello Robert welcome to the forum.:thumbsup:

Do you mean 810.21 (I)..?

Yes

K8MHZ · Mar 31, 2014

Would there possibly be a way to get the official definitions of 'operating ground' and 'protective ground' from the NFPA?

We are pretty much left to guess what they mean, and I don't think we should have to do that.

don_resqcapt19 · Mar 31, 2014

K8MHZ said:
Would there possibly be a way to get the official definitions of 'operating ground' and 'protective ground' from the NFPA?

We are pretty much left to guess what they mean, and I don't think we should have to do that.

You could try to get a formal interpretation, but there are specific rules and your question must be formated in a manner so it can be answered "yes" or "no". A call to the NFPA staff would get you an informal answer, or you could submit "public inputs" (proposals) for the 2017 code and see what the panel statements say when the "first draft" (ROP) comes out.

You could also look the the ROPs and ROCs from when the language became part of the code and see what the substantiations and panel comments said.

K8MHZ · Mar 31, 2014

don_resqcapt19 said:
You could try to get a formal interpretation, but there are specific rules and your question must be formated in a manner so it can be answered "yes" or "no". A call to the NFPA staff would get you an informal answer, or you could submit "public inputs" (proposals) for the 2017 code and see what the panel statements say when the "first draft" (ROP) comes out.

You could also look the the ROPs and ROCs from when the language became part of the code and see what the substantiations and panel comments said.

I just talked to a nice lady at the NFPA. She couldn't give me a direct answer because I am not an NFPA member, but she told me to e-mail the question to her and she would see what she could do.

If you are an NFPA member, they will transfer you to the appropriate department so you can talk to one of the engineers.

K8MHZ · Mar 31, 2014

don_resqcapt19 said:
You could try to get a formal interpretation, but there are specific rules and your question must be formated in a manner so it can be answered "yes" or "no". A call to the NFPA staff would get you an informal answer, or you could submit "public inputs" (proposals) for the 2017 code and see what the panel statements say when the "first draft" (ROP) comes out.

You could also look the the ROPs and ROCs from when the language became part of the code and see what the substantiations and panel comments said.

What's really daffy about the terms is that the only ground on a radio is for protection. There is no need for a ground to operate. Some antennas have radials slightly below grade, but the same antenna could be used totally above ground with the earth's function replaced by elevated radials. Even in the configuration that uses buried radials for operation, they are connected directly to the feed point of the antenna, there is no conductor to them. The radials don't even have to be buried. They can be laid flat on the ground. We bury them to keep the lawn mower from eating them. On top of that, the radial wires are often insulated, so the wire doesn't even touch the earth, the earth is just supporting the radials.

K8MHZ · Mar 31, 2014

Here is the reply I got from the NFPA

Technically there is no difference, both terms refer to the bonding conductor (or bonding grounding electrode conductor) used to bond between grounding electrodes (rod to rod or rod to concrete encased electrode (see 250.52). The term is based on language used in European standards where protective ground or protective bonding is used where the grounding electrode system is specified in US standards. An effort was initiated in NFPA 79 to use such IEC terms wherever a grounding term was used. However, it just created confusion and such terms were put into an Annex for the 2015 edition of NFPA 79 along with explanations for their use in the IEC standards. See the information figure 800(a) and 800(b) for an example of such bonding conductors. Protective grounding (earthing) is another IEC term for the grounding electrode system in US standards. The reference in 800.58 refers in one mode the connection to earth for operating with regard to the lead-in conductors and the other simply for protection similar to the grounding electrode system in 250.50.

Mark Cloutier
Sr. Electrical Engineer

So, it looks like I am the one that had it backwards. I think. I am going to write back for clarification. Because of this:

NEC : "The size of the protective grounding conductor......shall be as large as the lead-in....."

Mr. Cloutier: "The reference in 800.58 refers in one mode the connection to earth for operating with regard to the lead-in conductors"

NEC: "The operating grounding conductor for transmitting stations...." (lead-ins not mentioned)

Mr. Cloutier: "and the other simply for protection similar to the grounding electrode system in 250.50."

K8MHZ · Mar 31, 2014

OK,

I sent out another e-mail to Mr. Cloutier and got a response already. I am very much impressed by that.

His response was that he was going to request help from CMP 16 to answer my question.

I will post here with a follow up if one makes it's way to my e-mail box.

Terminology

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