Another dreaded grounding question. Grounding to copper bus bar

Here is the whole article but #10 is rthe minimum size required. Also take note of "A" where it talks of the material to be used.

810.21 Bonding Conductors and Grounding Electrode Conductors ? Receiving Stations. Bonding conductors or grounding electrode conductors shall comply with 810.21(A) through (K).
(A) Material. The bonding conductor or grounding electrode conductor shall be of copper, aluminum, copper-clad steel, bronze, or similar corrosion-resistant material. Aluminum or copper-clad aluminum bonding conductors or grounding electrode conductors shall not be used where in direct contact with masonry or the earth or where subject to corrosive conditions. Where used outside, aluminum or copper-clad aluminum conductors shall not be installed within 450 mm (18 in.) of the earth.
(B) Insulation. Insulation on bonding conductors or grounding electrode conductors shall not be required.
(C) Supports. The bonding conductors and grounding electrode conductors shall be securely fastened in place and shall be permitted to be directly attached to the surface wired over without the use of insulating supports.
Exception: Where proper support cannot be provided, the size of the bonding conductors and grounding electrode conductors shall be increased proportionately.
(D) Mechanical Protection. The bonding conductors and grounding electrode conductor shall be protected where exposed to physical damage. Where the bonding conductor or grounding electrode conductor is run in a metal raceway, both ends of the raceway shall be bonded to the contained conductor or to the same terminal or electrode to which the conductor is connected.
(E) Run in Straight Line. The bonding conductor or grounding electrode conductor for an antenna mast or antenna discharge unit shall be run in as straight a line as practicable.
(F) Electrode. The bonding conductor or grounding electrode conductor shall be connected as required in (F)(1) through (F)(3).
(1) In Buildings or Structures with an Intersystem Bonding Termination. If the building or structure served has an intersystem bonding termination as required by 250.94, the bonding conductor shall be connected to the intersystem bonding termination.
Informational Note: See Article 100 for the definition of Intersystem Bonding Termination.
(2) In Buildings or Structures with Grounding Means.
If the building or structure served has no intersystem bonding termination, the bonding conductor or grounding electrode conductor shall be connected to the nearest accessible location on the following:
(1) The building or structure grounding electrode system as covered in 250.50
(2) The grounded interior metal water piping systems, within 1.52 m (5 ft) from its point of entrance to the building, as
covered in 250.52
(3) The power service accessible means external to the building, as covered in 250.94
(4) The nonflexible metallic power service raceway
(5) The service equipment enclosure, or
(6) The grounding electrode conductor or the grounding electrode conductor metal enclosures of the power service


A bonding device intended to provide a termination point for the bonding conductor (intersystem bonding) shall not interfere
with the opening of an equipment enclosure. A bonding device shall be mounted on non-removable parts. A bonding device shall not be mounted on a door or cover even if the door or cover is non-removable.
(3) In Buildings or Structures Without an Intersystem Bonding Termination or Grounding Means. If the building or structure served has no intersystem bonding termination or grounding means as described in 810.21(F)(2), the grounding electrode conductor shall be connected to an electrode as described in 250.52.
(G) Inside or Outside Building. The bonding conductor or grounding electrode conductor shall be permitted to be run either inside or outside the building.
(H) Size. The bonding conductor or grounding electrode conductor shall not be smaller than 10 AWG copper, 8 AWG aluminum, or 17 AWG copper-clad steel or bronze.
(I) Common Ground. A single bonding conductor or grounding electrode conductor shall be permitted for both protective
and operating purposes.
(J) Bonding of Electrodes. A bonding jumper not smaller than 6 AWG copper or equivalent shall be connected between the radio and television equipment grounding electrode and the power grounding electrode system at the building or structure served where separate electrodes are used.
(K) Electrode Connection. Connections to grounding electrodes shall comply with 250.70.

Thanks for all the great info and input! I used to do electrical work but my NEC book is from , glad to see nothing has changed! It's funny that some mentioned copper strap. I spoke to someone at Polyphaser who recommended copper strap for the whole job (tower legs, ring, and the run to the house), so I ordered 200' of 2" X .032" copper strap from Georgia copper. The AHJ wouldn't allow it (He said it "didn't look heavy enough to take a strike") and told me I had to use 2/0 or larger wire. :rant: So I paid to ship the strap back, luckily I hadn't opened the packages, so I was only out the shipping both ways.
It took 23 months, several battles, and more money than I wish to think about to finally get the permit for the tower. I'm glad to hear that tin plated copper is fine, it only stands to reason because, if the manufacturer is plating a copper ring with tin, there shouldn't be any dissimilar metal issues, or so I also believed. I'll be using stainless steel bolts for the ring connections.
LOL, for the bus bar I did mean 2" X 15" :ashamed1:.
Thanks again for all the help and any further comments or advice is greatly appreciated!

Tim (AA2HA)" x .032"2"

Polyphaser is correct, your AHJ is wrong.

2/0 is useless against a lightning strike.

If you value your equipment you need to get an engineered design for lighting protection and if the AHJ has a problem with using flat strap, take it over his head.

FWIW, I got involved with the 200 foot tower in the pic at the request of a lawyer from Harvard U. (Yes, THE Harvard University) His friend, a doctor, owns the tower and the township was giving the good doctor grief about it and threatening legal action. So the good Doc Joe calls Fred the big shot lawyer and Fred said Joe needed a Michigan State licensed electrician that held an FCC Amateur Extra class license as well to work things out, which I did.

So, I know for sure that local AHJs are in no position dictate lightning protection systems for 100 foot plus tall towers, but sometimes they act like they are, and they can make life miserable for hams putting up big towers. The truth of the matter is that the AHJ probably has neither training nor experience in lightning protection systems and thus, has no business inspecting them.

If you decide to cave in to the AHJ, make sure you have lots of insurance.

FWIW, a .030" flat strap 6 inches wide will shunt a direct lightning hit without fusing open. Do you think that the 2/0 will do the same? (Think 'skin effect').

Good luck! Your AHJ is lucky he is dealing with you and not me, that's for sure!

The AHJ wouldn't allow it (He said it "didn't look heavy enough to take a strike") and told me I had to use 2/0 or larger wire.

Code reference?

Besides Polyphaser (which is an A1 company), check out Tom W8JI's site on ham station grounding:

http://w8ji.com/station_ground.htm

You can see in the pics where he is using copper flashing and braided strap.

Remember, although lightning is technically DC, is acts like it is 100MHz AC and has a very pronounced skin effect. It also runs about 100 plus kV and 100 plus kA. A run of 2/0 subject to that will fuse open, create an arc and pose a greater risk than it supposedly is installed to mitigate. The physics of lightning and the physics of 60Hz AC mains are worlds apart and thus, the materials used in each may be worlds apart as well.

It's your choice, but if I had a 100 foot tower and was not allowed to properly protect my person and property due to the incompetence of an AHJ, fur would be flying.