2005 NEC 250.50

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inspector44

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2005 NEC section 250.50 says where available footer reinforcement shall be used as a grounding electrode.I took a look at the 2002 NEC handbook and found a 1978 clarification listed, stating the intent was not to require re bar as a mandatory electrode. Looking for clarification. (As this relates to new construction with re bar in new footings)
 
Re: 2005 NEC 250.50

You are correct about the official interpretation. The intent was to use the concrete encased electrode if it was installed but not to break into the footer if it wasn't brought out. It has become the general rule to just forget about ever using the concrete encased electrode. Therefore, Code Making Panel 5 has changed the rule to require its use if it has been installed in the footer . . . period.

Once the building contractors realize that they will have to go back and break up the footer to gain access, they will start requiring the concrete people to turn up a piece of rebar for access later. This is going to be a big deal for a short period of time and then become a non-issue. It will even save the cost of ground rods since they will not be needed any more. :D
 
Re: 2005 NEC 250.50

I like the idea. :)

Edit: Except the concrete guys will probably put the exposed rebar as far as possible from the service. :D

[ February 10, 2005, 01:52 PM: Message edited by: physis ]
 
Re: 2005 NEC 250.50

It will potentially create an additional inspection. Also not all foundations in my area have steel so there will be confusion regarding notification.As Charlie said for a little while anyway!!

Charlie
 
Re: 2005 NEC 250.50

On the jobs we do the structural engineer will go ballistic if we start breaking into a footing that is monolithic. :D
 
Re: 2005 NEC 250.50

As a PE, I always call for attachment to rebar in new construction, and at least 25% of the time, the contractor calls and asks me to write an addendum saying it is OK to skip the rebar because they didn't "get a chance" to attach to it.
I look forward to the 2005 being adopted, because now I have Code backing my reluctance to write the addendum.
I suspect the structural engineer can design a fix for the foundation, it's just that the Contractor isn't going to like it.
Jim T
 
Re: 2005 NEC 250.50

By Iwire:

On the jobs we do the structural engineer will go ballistic if we start breaking into a footing that is monolithic.
Click to expand...
I don't blame him. And he probably wont leave out that peice of exposed rebar more than once. ;)
 
Re: 2005 NEC 250.50

Article 250-81, from 1978 said that reinforcing steel in building footers was not intended to be used as grounding, so where does it state in the 2005 issue that the rebar shall be grounded. I do understand that if there is a concrete-encased electrode, then that has to be grounded to all electrodes. Please help clarify.
Thanks!
 
Re: 2005 NEC 250.50

Read 250.50 in the 2005 NEC...it uses the wording "that are present" instead of the term "if available" that is in 2002 NEC.

The new exception excludes concrete-encased electrodes in exsisting buildings.

shortcircuit2
 
Re: 2005 NEC 250.50

But what is the codes true intent for 250.50 - where 250.52(a)1thru6 are present they must be bonded. Specifically 250.52(a)(3), I understand the UFER system, when needed.
But if you are using (a)1,2,4 is (3) necessary.
Our structural engineer has suggested that tying to his rebar in concrete will induce currents which over time will corrode the rebar
 
Re: 2005 NEC 250.50

Originally posted by harlangto:
But what is the codes true intent for 250.50 - where 250.52(a)1thru6 are present they must be bonded. Specifically 250.52(a)(3), I understand the UFER system, when needed.
But if you are using (a)1,2,4 is (3) necessary.
Our structural engineer has suggested that tying to his rebar in concrete will induce currents which over time will corrode the rebar
Click to expand...
Yes - it is necessary if present...that is pretty clear.

In our area it is always present - because the inspector won't sign off the foundation inspection until the Ufer is installed. (We're in earthquake country so there is always steel in the foundation).

"corrode the rebar" ?? I think your engineer is missing a few of those electrons.
 
Re: 2005 NEC 250.50

I said he was structural.
It's just an in-house dispute over the whole topic.
OK as far as 250.52(a)(3) - how is your rebar coated,ie: "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"?
 
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