690.12(B)(1), Distance from Point of Entry measurement

[MikeNZ]

Hi Guys,

Just a quick question about 690.12(B)(1), if we had an FMC coming from the point of entry, that was longer than 1m/3ft(say 1.5m), but installation guidelines required installers to install the RSS within the 1m/3ft, would that be ok from an AHJ point of view? or would the system not be certifiable because the RSS can theoretically be installed outside 1m/3ft from the point of entry?

I realize this may come down to individual AHJ decisions, but educated guesses will be appreciated in that case.

 

[jaggedben]

I don't really follow the question. Whatever is serving the RSS function cannot be installed farther than 3ft from the point of entry. NEC requirements generally pertain to what is actually installed, not what can 'theoretically' be installed.

 

[MikeNZ]

I don't really follow the question. Whatever is serving the RSS function cannot be installed farther than 3ft from the point of entry. NEC requirements generally pertain to what is actually installed, not what can 'theoretically' be installed.

That's what makes sense to me too, so its up to the installing electrician to ensure the RSS is inside the 3ft boundary, even if the supplied kit had say 4ft of FMC to allow for obstructions?

 

[jaggedben]

I'd say yes to that.

 

[pv_n00b]

It's the old question, are they talking about conductor length or physical distance? This is what causes all kind of AHJ interpretation problems. If it's physical distance then you can have a hundred feet of conductor curled up next to the point of entry and it's still within 1m.

 

[ggunn]

It's the old question, are they talking about conductor length or physical distance? This is what causes all kind of AHJ interpretation problems. If it's physical distance then you can have a hundred feet of conductor curled up next to the point of entry and it's still within 1m.

I always consider such rules to be "as the conductor flies".

 

[pv_n00b]

I always consider such rules to be "as the conductor flies".

Typically I see people interpreting it whichever way lets them install the project they are working on that day.

 

[MikeNZ]

Thanks for your answers guys, that's what I figured but always good to check with the pros.

One more thing on the subject, what would be the earthing requirements on that FMC? our system is un-grounded (has no exposed metal), also would the FMC need to be UL listed?
690.31 (G)(2) does not mention listed materials being required but I thought it may somewhere else.

 

[jaggedben]

Yes, you need to bond the FMC. That is basic article 250 stuff, reinforced in 690.43.