Grounding Electrode question

[knockadse]

2005 NEC 250.52 A(3)

An electrode encased by at least 2in of concrete, located within and near the bottom of a concrete foundation or footing that is in direct contact with the ears, consisting of at least 20 ft of one or more bare or zinc galvanized or other electrically conductive coated steel reinforcing bars or rods........

Question - Does this section indicate that a special type of coated reinforcing bar must be used instead of the normal rebar?

If so what do you see in your jurisdiction to comply with this section ? (use 20' of 4 AWG placed in the footing?)

Thank you in advance for your help

 

[georgia plans exam]

Re: Grounding Electrode question

It say's "bare or".

GPE

 

[fatboy]

Re: Grounding Electrode question

I don't have a NEC in front of me........I don't recall the "coated" part of that section, I'll have to look it up when I get back. We see, and accept regular rebar here.

 

[FredK]

Re: Grounding Electrode question

Copper.

 

[north star]

Re: Grounding Electrode question

knockadse,

If installing a [ typical ] length of ' rebar ' in a footing, all deposits [ i.e. - mud, grease, oils, etc. ] and rust

should be removed. This will allow/promote the greatest conductivity path along the length of

the installed reinforcement.

 

[knockadse]

Re: Grounding Electrode question

That section uses the word or too frequently.

Thanks for clearing that up.

 

[D a v e W]

Re: Grounding Electrode question

#4 rebar is still acceptable same as 2005 no change in 2008 edition

2008 NEC 250.52 (A) (3) Concrete-Encased Electrode. An electrode encased by at least 50 mm (2 in.) of concrete, located horizontally near the bottom or vertically, and within that portion of a concrete foundation or footing that is in direct contact with the earth, consisting of at least 6.0 m (20 ft) of one or more bare or zinc galvanized or other electrically conductive coated steel reinforcing bars or rods of not less than 13 mm (1/2 in.) in diameter, or consisting of at least 6.0 m (20 ft) of bare copper onductor not smaller than 4 AWG. Reinforcing bars shall be permitted to be bonded together by the usual steel tie wires or other effective means. Where multiple concrete-encased electrodes are present at a building or structure, it shall be permissible to bond only one into the grounding electrode system.

 

[TCN]

Re: Grounding Electrode question

The typical 1/2" (#4) bar is usable. 20' can be accomplished through the steel tie wires. "Reinforcing bars shall be permitted to be bonded together by the usual steel tie wires or other effective means." Though I wouldn't be comfortable with one perpendicular tie, if it is tied more often and appears to make good bonding contact by 'other effective means', then practically and electrically it can be considered the same by 250.52(A)(3) as quoted earlier.

 

[FredK]

Re: Grounding Electrode question

Well I'll have to change my answer since yesterday the first rebar ufer was installed. They are using special 25 ft rebar bent at 20 ft with a 5 ft return.

Now the Million$$ question will any hex nut connection work and how to tell if not?

 

[raider1]

Re: Grounding Electrode question

Well I'll have to change my answer since yesterday the first rebar ufer was installed. They are using special 25 ft rebar bent at 20 ft with a 5 ft return.Now the Million$$ question will any hex nut connection work and how to tell if not?

What do you mean by "Hex nut connection"?

If you are refering to a split bolt then the split bolt would need to be listed for use with re-bar and to be buried in concrete.

Chris

 

[globe trekker]

Re: Grounding Electrode question

Agree with raider1! The split bolt WOULD need to be approved for that type installation. Most of the

ones that I have seen have been brass. See the link.

http://www.meetindustries.co.in/Splitbo ... inetap.htm

.