Rebar to ground GRID requirements

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Mike to qualify as a CEE it technically must be part of the footing or foundation. I know that all electrodes present at the building must be used. We can also start another argument with Mike Whitt as to whether an electrode on the property, not part of the building, needs to be used. We are not going there again :lol:. I don't see this as an CEE but it certainly wouldn't hurt to use it.
 
I don't see this as a grounding electrode issue. I don't see it as a NEC issue. It still looks like a bonding grid for step and touch potential safety. That is not covered by the rules in the NEC. While this system is likely actually covered by the NEC, you should look to the NESC for information on rules like this.
This is a design and a safety issue and needs to be addressed by the engineer.
 
Dennis Alwon said:
I did not pick up from the OP that the grid was cut. I understood that this is a new project and they want to utilize the grid in the roadway and tie it to the grounding system. This is not a requirement as the rebar in the roadway is not a ufer. That was my interpretation of what is going on.
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We have a large 800'+ by 1600'+ site ground GRID/MAT. A contractor we have hired is installing a very thick (3'+) rebar reenforced concrete roadway (for a 200T transporter) through the ground grid
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The question is whether (and how) the grounding grid was compromised. With the concern expressed, I guess it was compromised, and as a remedy, it is desired to bond the grid to the roadway rebar. What you call it once bonded is irrelevant.
 
I think we are all on the same page but using a different basis in cases.Yes I was speaking of the road concrete's internal rebar being bonded to the plant grid and if so doesn't that make the road a huge ufer ground?

dick
 
Still unknowns ,do we have a substation close by that may contribute to step and touch potentials.I have forgotten the parameters of distances for clearance safety distances.It also may have already been addressed with a mat or crushed stone.

dick
 
Clearly if the mat was installed as a grounding mat grid and the contractor broke the continuity of the grid then yes it should be repaired , but it is not an NEC issue. I think the contractor should be liable to connect it back.
 
Rebar to ground GRID requirements

Yes, the ground mat IS part of a Substation and Power Plant ground grid. The roadway is NOT cutting the existing primary conductors of the ground grid (4 x 750mcm Cu conductors), but is removing the #8 mat grid 6" below the crush 'n' run surface. I see now that NEC 250.52 does not apply as we are a power plant, but I care deeply about my technicians and their safety. Others have recommended I look at IEEE 665 and 142 along with NESC-2007 section 9 rule 094, but I don't have copies readily available. Based on y'all's conversation, my take away is that insisting on connecting the rebar to the grounding mat is the RIGHT THING to do, but it won't be found in the NEC 250 codes.
 
I don't know if it is the right thing to do or not. It seems like it ought to be kicked up to engineering to take a look at what is being done (or has been done) and how it may or may not matter.

A lot of times people obsess over things that bother them that are not that big of a deal and don't worry about things that really do matter. Without a close look by qualified individuals, no one will know if there is a problem or not.
 
Jeffro Wagner said:
... but is removing the #8 mat grid 6" below the crush 'n' run surface... .
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That type of grid is installed to help protect workers from step and touch potentials. Engineering review may tell you that you don't need that type of protection where the new roadway is being installed.
 
Don he says the roadbed installation is compromising that area of protection at that point.I'm sure the safety mat is still intact but now the road bed is in that once protected area.I feel (gut feel) that at the area of compromise the rebar should be bonded to the mat at distances not exceeding the dimensions of the grid.JMO no backup at this juncture it is best to error to the positive. The company /contractors involved should have engineering personnel available to put this issue to bed.

dick
 
dicklaxt said:
Don he says the roadbed installation is compromising that area of protection at that point.I'm sure the safety mat is still intact but now the road bed is in that once protected area.I feel (gut feel) that at the area of compromise the rebar should be bonded to the mat at distances not exceeding the dimensions of the grid.JMO no backup at this juncture it is best to error to the positive. The company /contractors involved should have engineering personnel available to put this issue to bed.

dick
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why is the "best" thing to do to make an error? that is not "best". It is just an error. The best thing is to have someone qualified take a look.
 
dicklaxt said:
Don he says the roadbed installation is compromising that area of protection at that point.I'm sure the safety mat is still intact but now the road bed is in that once protected area.I feel (gut feel) that at the area of compromise the rebar should be bonded to the mat at distances not exceeding the dimensions of the grid.JMO no backup at this juncture it is best to error to the positive. The company /contractors involved should have engineering personnel available to put this issue to bed.

dick
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I agree that this needs engineer evaluation, but I just can't imagine the roadway being installed in the area that actually requires the bonding grid to reduce the step and touch potential.

If that protection is needed, then even the design of the concrete road and its re-bar will have to be looked at. The re-bar that is being installed for the structural strength of the road may not be suitable to provide the required step and touch protection. It may not be close enough to the surface of the concrete.
 
Error meaning ,when no alternatives are forthcoming...I agree the roadbed would be a poor substitute for that protection but then again if done properly it could be integral to the mat...............lots of outs ,,,get engineering involved,This is not in the contractors baliwick(sp)

dick
 
dicklaxt said:
Error meaning ,when no alternatives are forthcoming...I agree the roadbed would be a poor substitute for that protection but then again if done properly it could be integral to the mat...............lots of outs ,,,get engineering involved,This is not in the contractors baliwick(sp)

dick
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I said that back in post #6.

I just checked the OP/PM'ers occupation... Electrical Design Engineer :huh:
 
Rebar to ground GRID requirements

As I suspected in the beginning, this is an issue that needs a true engineering evaluation and with y'all's threads I have enough (based on MikeHolt.com reputation) confirming discussion that I can push to get it done. Thanks!!!
 
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