Stone floors in kitchen and hearth grounding.

[gulf0927]

Have a new custom build coming up. They will have stone floors in the kitchen supported by a rebar system, and then a stone floor area in front of the fireplace in a separate room. I would think that both of these rebar systems get bonded together and then go back to the service equipment/grounding electrode system. However, the customer and GC are saying they want them to each be their own system with separate ground rods, not bonded back to the service. I don't think this works with the code, and haven't done one like this before. Any input is appreciated!

 

[winnie]

Why do you think they need to be bonded at all? Do these rebar systems meet the definition of concrete encased electrodes, or is there a circuit likely to energize them, or is there a spa you forgot to mention?

Rebar in concrete isolated from soil generally doesn't need to be grounded or bonded.

If for some reason it does need to be bonded, then you can't use separate electrodes. Separate electrodes doesn't meet code and is often more dangerous than no electrodes at all.

 

[infinity]

No bonding of a slab is required unless there is a pool involved.

 

[curt swartz]

Why bond them at all? What purpose would it serve?

 

[don_resqcapt19]

However, the customer and GC are saying they want them to each be their own system with separate ground rods, not bonded back to the service. I don't think this works with the code,

The code doesn't care as these are not grounding electrodes and there are no rules on bonding the rebar in these slabs and there is no reason to bond them. However if you do, having isolated grounding electrodes can result in a high voltage potential between them and anything connected to the electrical grounding/bonding system in the event of a near by lighting strike. Separate electrodes can have thousands of volts between them under that condition.
If you do ground and bond them, you should tie them all together and to the electrical grounding and bonding system

As others have said there is no reason to make those bonds.

 

[infinity]

If you follow what Don has stated you'll see that nothing is far safer than installing something incorrectly.

 

[electrofelon]

Everyone is all nuts about grounding and bonding, but remember you are connecting something to an electrical system - its not all good, bad things can happen.

 

[Dsg319]

Everyone is all nuts about grounding and bonding, but remember you are connecting something to an electrical system - its not all good, bad things can happen.

yep, open neutral and the next you know your kitchen floor is all tingly feeling.

 

[winnie]

But back to the original post.

I reread my response and realized that it could be taken as 'haha you stupid *--$*, don't you know that you don't have to bond that rebar', and that is exactly the opposite of what I intended.

We are not on site, and can't know the full situation. There are situations where that rebar must be bonded, and I was really asking 'What about the situation is making you say you need to bond the rebar?' while also saying that such situations are uncommon.

 

[ptonsparky]

You're not required to, but it certainly would have some advantages. Mainly reduction in step or touch potential. That tingly feeling will not be there while you're on it. Put 400 amps below your feet. Nope. Bird on a wire, until you touch something not included in that plane.

 

[don_resqcapt19]

Mainly reduction in step or touch potential.

Or increase the touch potential to other conductive objects that are not connected to the bonding/grounding system. Remember that when we are connecting it to the electrical system we are actually energizing it.