Maximum bonding distance between two electrodes

[diydish]

I will be driving an 8' rod near the ground block at the house. The ground rod will be on the same side as the electric service. They are about 60 feet from each other in a straight line with no obstructions. NEC says I must bond the two electrodes with #6 bare copper wire. But the code does not say what the maximum distance between the two elctrodes should be. Will bonding at that distance be ineffective or does it matter in a situation like this since the code doesn't say?

 

[markspace]

Keep in mind that the NEC is largely about safety (functionality is important, but safety is foremost). The 60' run of #6 should keep both at the same ground potential, and even if it absorbs a lightening strike (that *is* why you're putting in the 2nd rod, right?), about the worst case is the #6 would be a fuse.

 

[larrystotler]

NEC code requires that you install ground rods every 20 feet from the main house ground and that all grounds be bonded to the main house ground. If you are going 60 feet, you will need a total of 3 ground rods to meet code. Check with your local inspections department to see if their regulations supercede NEC tho.

 

[IAMTHEEGGMAN]

NEC code requires that you install ground rods every 20 feet from the main house ground and that all grounds be bonded to the main house ground. If you are going 60 feet, you will need a total of 3 ground rods to meet code. Check with your local inspections department to see if their regulations supercede NEC tho.

. Never heard of the requirement to drive rods every 20 feet. Can you site this code section??

You don't need to drive another ground rod. Another ground rod will exceed code so it won't hurt. Remember NEC is minimun requirement. Wire runs for things in a basic house house can exceed 60 feet, voltage drop at that length is minimal. My suggestion is the hire an licensed electrician if you don't understand grounding. Life safety is no joke.

 

[diydish]

I was just estimating the distance between the two electrodes. Today I did the actual measurement and it's really just 45 feet.

I saw an example drawing somewhere that showed a long run on opposite ends of a house (not in a straight line) and it suggested one conductor between the two while emphasizing a straight line as possible. I'll see if I can find that info again and post it here.

 

[larrystotler]

I can't find the reference. Please check with your local inspector on the local requirements. That is the best and safest option.

 

[Mike500]

I was just estimating the distance between the two electrodes. Today I did the actual measurement and it's really just 45 feet.

I saw an example drawing somewhere that showed a long run on opposite ends of a house (not in a straight line) and it suggested one conductor between the two while emphasizing a straight line as possible. I'll see if I can find that info again and post it here.

45 feet should be fine, as long as you use #6 copper to connect them together. That distance should be better, as long as you bury the wire at least 12 inches below the surface. As I recall, another section of the NEC allows for a large #2 copper conductor to be the only required electrode, if it surrounds the entire building. The 20 foot rule relates to the distance of the ground wire for the grounding block of the satellite system from the grounding electrode and has nothing to do with the second ground rod, which, if made continuous with a #6 or larger conductor, enhances and excedes the NEC requirement.

Just be sure that you use the correct size UL listed grounding clamps rated for direct burial and bury the entire 8 ft length of the grounding rod. Only one wire should be attached with one clamp. Using nore than one clamp to attach the wire is not a bad idea. Also, after clamping the added conductor to the original rod and making the conductor longer and runnig it parallel to the original grounding wire and bonding the two together with UL listed copper split bolts may not be a bad idea.

I use Thomas and Betts non removable copper "c" taps, but the tool for crimping them is very expensive. As long as the original conductor is not spliced with removable clamps, you are fine.

 

[diydish]

That distance should be better, as long as you bury the wire at least 12 inches below the surface.

Is it code that the wire must be buried? I don't remember reading that.

 

[diydish]

Lowes has #6 copper in 25' coils. Can I just splice them together since it's a bonding jumper and not a GEC?

 

[SCOOTERZ56]

This is what the code says:

The bonding conductor must comply with 250.64 (C).

(C) Continious. Grounding electrode conductor(s) shall be installed in one continuous length without a splice or joint except as permitted in (1) through (4):

(1) Splicing shall be permitted only by irreversible compression-type connectors listed as grounding and bonding equipment or by the exothermic welding process.

So to answer your question, yes you can splice the bonding conductor but the crimp tool and connectors will cost you more than a roll of #6.

 

[diydish]

I need to know which AWG would be better. On a 45 foot run would #4 be better than #6? Also does it matter if the wire is solid or stranded?

Thanks everybody for your help.