Ground rods

[hhsting]

Attached diagram shows incoming 3 sets 500kcmil AL service conductors to service disconnect.

It also shows the GEC from service disco to underground metal water pipe, a bonding jumper from the metal pipe to the ground rods and bonding jumper between ground rods.

Question is the bonding jumper between ground rods is it sized per Table 250.66 or #6awg cu is ok?

 

[LarryFine]

#6 copper is always large enough for rods, both the GEC to the first rod and the jumper between rods.

 

[Dennis Alwon]

I am having a hard time reading the sketch. Are you proposing running aluminum to the ground rods?

 

[hhsting]

I am having a hard time reading the sketch. Are you proposing running aluminum to the ground rods?

Either #4 AL or #6 CU.

Sent from my SM-G935U using Tapatalk

 

[Cow]

Either #4 AL or #6 CU.

Sent from my SM-G935U using Tapatalk

Where did you come up with aluminum to rods?

 

[hhsting]

Where did you come up with aluminum to rods?

Oh in 250.66(A) , 250.53(E) says #6 Awg or #4 Awg AL. Not sure it apply to the sketch post #1 where "?" is marked.

 

[Mouser]

May want to see if your aluminum GEC and jumper complies with 250.64(A)

 

[Dennis Alwon]

Aluminum cannot be terminated within 18" of the earth

250.64(A) Aluminum or Copper-Clad Aluminum Conductors. Bare
aluminum or copper-clad aluminum 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
grounding electrode conductors shall not be terminated within
450 mm (18 in.) of the earth.

 

[hhsting]

Aluminum cannot be terminated within 18" of the earth

I thought what I have to ground rods is bonding jumper not grounding electrode conductor.

So what does that mean I cannot use #4 Al GEC to ground rods?

Sent from my SM-G935U using Tapatalk

 

[LarryFine]

I thought what I have to ground rods is bonding jumper not grounding electrode conductor.

No. The bonding jumper is that which connects the neutral to the grounding electrode and equipment grounding system(s). It's not always a wire.

So what does that mean I cannot use #4 Al GEC to ground rods?

Not to the rods, because aluminum may not be terminated within 18" of the earth, as stated above.

 

[hhsting]

No. The bonding jumper is that which connects the neutral to the grounding electrode and equipment grounding system(s). It's not always a wire.

/*****What you are referring to above is main bonding jumper. Their is a difference between main bonding jumper and bonding jumper. Code even says bonding jumper can be used to connected together electrodes to create grounding electrode system. Bonding jumper bonds two electrodes and is wire.*****/

Not to the rods, because aluminum may not be terminated within 18" of the earth, as stated above.

/*****Why then code calls for use for ground rods, plate electrodes #6awg or #4 Al post #6****/

Please see text after "/***" response.

Sent from my SM-G935U using Tapatalk

 

[LarryFine]

Yes, I was referring to the main bonding jumper. My apologies.

According to 250.64(A), aluminum cannot be within 18" of earth outdoors. Not all GECs are outdoors or connected to rods.

 

[Dennis Alwon]

It doesn't matter what you call it because aluminum must be terminate more than 18" from the ground

 

[infinity]

If you insist on an aluminum GEC to the rods then the rod need to be 10' long and pounded in to a depth of 8', that would keep the aluminum GEC above 18".

 

[Dennis Alwon]

/*****Why then code calls for use for ground rods, plate electrodes #6awg or #4 Al post #6****/

Because as Trevor stated you can run aluminum to the rod but it must be 18" above grade-- 10' rod but then you would probably need to protect it.

250.10 Protection of Ground Clamps and Fittings. Ground
clamps or other fittings exposed to physical damage shall be
enclosed in metal, wood, or equivalent protective covering.

250.64(B)(2) Exposed to Physical Damage. A 6 AWG or larger copper
or aluminum grounding electrode conductor exposed to physical
damage shall be protected in rigid metal conduit (RMC),intermediate metal conduit (IMC), rigid polyvinyl chloride
conduit (PVC), reinforced thermosetting resin conduit Type
XW (RTRC-XW), electrical metallic tubing (EMT), or cable
armor.

 

[hhsting]

Because as Trevor stated you can run aluminum to the rod but it must be 18" above grade-- 10' rod but then you would probably need to protect it.

What I have is bonding jumper from metal underground water pipe to ground rods not grounding electrode conductor.

Where in code it says to protect bonding jumper?

Sent from my SM-G935U using Tapatalk

 

[Dennis Alwon]

What I have is bonding jumper from metal underground water pipe to ground rods not grounding electrode conductor.

Where in code it says to protect bonding jumper?

Sent from my SM-G935U using Tapatalk

Read 250.10-- That is if the rod is above ground as Infinity stated above.... You have to protect the clamp if it is above grade. I think you should scrap the aluminum and use copper and not worry about any of it. Dive rod below ground with clamp and you are good.

 

[lordofthisworld]

What I have is bonding jumper from metal underground water pipe to ground rods not grounding electrode conductor.

Where in code it says to protect bonding jumper?

Sent from my SM-G935U using Tapatalk

Is your underground water pipe your main electrode? Or do u have building steel?

 

[hhsting]

Is your underground water pipe your main electrode? Or do u have building steel?

No building steel. Underground metal water pipe main electrode and ground rods supplemental electrode.

 

[LarryFine]

No building steel. Underground metal water pipe main electrode and ground rods supplemental electrode.

You need full-sized conductor between main disco and water pipe, only #6 cu between main and rods or between water pipe and rods.