Grounding with exothermic weld.

[kencoel]

I have a small electrical room for all the distribution panels and homerun conduits that limit the remaining floor space. The specifications require four ground rods looped together and connected by exothermic welds to the rods.

Can the welded condutors to the rods be cast below the electrical room concrete slab or must they be accessible?

 

[kingpb]

Exothermic welds are suitable for below ground/grade installation, and do not require access after installation.

Refer to ERICO website (makers of Cadweld products)

 

[barbeer]

for NEC's version, 250.68(A) exception 1

 

[Denis]

exception 1 is concrete related
exception 2 is "Exothermic or irreversable compression connections used as terminations, together with the mechanical means used to attach such terminations to fire-proofed structural metal whether or not the mechanical means is reversible, shall not be required to be accessable."

 

[nakulak]

might wanna check your job specs though. we've done jobs where the ahj wanted all grounding connections accessible so their engineers could check them periodically and so included in specs

 

[barbeer]

exception 1 is concrete related

I beg to differ! There is specific mention of buried, driven......

 

[celtic]

I beg to differ! There is specific mention of buried, driven......

While exception 2 deals with "fire-proofed structural metal"....