AHJ and PV Disco Location

[beechigby]

NEC 100 suggests that Discos behind locked doors ARE considered "Readily Accessable"
art 690 suggests that pv dc conductors canbe disconnected inside a building if in metal conduit from PV to disco and have the disco near point of entrance of conductors
My AHJ wants a disco outside the building cause he says the locked door makes it NOT "Readily Accessable"
He wants the PV DC Disco outside, and an AC disco for non battery based GT systems as well.
the electric utility is waiving the requirement for a outside "Net Meter" disco for systems under 10Kw.
Im looking for examples to show and all specific code itmes to help convince him to lighten up
He is also thinking on haveing a bat Disco outside, in additon to the one by the inverter for bat based systems.
:weeping:

 

[tallgirl]

NEC 100 suggests that Discos behind locked doors ARE considered "Readily Accessable"
art 690 suggests that pv dc conductors canbe disconnected inside a building if in metal conduit from PV to disco and have the disco near point of entrance of conductors
My AHJ wants a disco outside the building cause he says the locked door makes it NOT "Readily Accessable"
He wants the PV DC Disco outside, and an AC disco for non battery based GT systems as well.
the electric utility is waiving the requirement for a outside "Net Meter" disco for systems under 10Kw.
Im looking for examples to show and all specific code itmes to help convince him to lighten up
He is also thinking on haveing a bat Disco outside, in additon to the one by the inverter for bat based systems.
:weeping:

These are being required in some jurisdictions due to the risk of roof-top fires. The idea being that a firefighter isn't going to be able to go into a building that's on fire to open the PV disco.

A few years back the local fire department was going door-to-door to raise money for something or other. I showed them all the disconnects on the side of the house and I'm not sure they were entirely amused. Getting into a house that's had the meter pulled and discovering that there's still electricity inside would likely be even less amusing. So ... good luck with getting rid of the external disconnect rule if they are doing it for firefighter safety.

 

[jaggedben]

I've worked in several jurisdictions that require DC disconnects on the roof according to local ordinance. Local jurisdictions can go beyond the code on issues like this, and I can't really say it's unreasonable. If they don't really have an official policy by ordinance or fire marshal decree then I suppose you could argue based on 690, but that's all you've really got.

Not entirely clear if you have batteries or not, but if you do, an outside disconnect is typical for firefighters as well. The outside AC disco is usually a utility requirement.

 

[beechigby]

I get that on a based system, an AC Disco for the Inv subpanel is approiate outside the structure.
But if the bat rm is on fire, whats the point?
Also, on the Microinverter system with little DC wiring, and 240Vac coming down off the roof, how is an outside Disco possibly construed as a safetydevice for fireman if all power export is discontineued when the line connection is opend (meter pulled)?
I install both bat based and batterless GT systems. the microinverter systems sure has the leasthoops to jump thru!

 

[tallgirl]

I get that on a based system, an AC Disco for the Inv subpanel is approiate outside the structure.
But if the bat rm is on fire, whats the point?
Also, on the Microinverter system with little DC wiring, and 240Vac coming down off the roof, how is an outside Disco possibly construed as a safetydevice for fireman if all power export is discontineued when the line connection is opend (meter pulled)?

It's possible that the battery space is inside a larger space, like an attached garage. The goal is to be able to turn off =all= power inside the building, which isn't possible with a battery based system unless the appropriate disconnects are outside the building that is on fire. The whole purpose of a critical loads panel is to survive a power outage, which includes when the meter is pulled or the input breakers are opened.

Keep in mind that you've got non-electricians going into a building that isn't well-lit, spraying water all over the place, and use big metal tools to smash through things. The last thing they need to deal with is electricity. String and central inverter vendors like to downplay the risks of fire, and the danger to firefighters, but the number of roof-top fires caused by high voltage strings says otherwise. Add to that battery-backed inverters that refuse to turn off and they have a lot to deal with.

I install both bat based and batterless GT systems. the microinverter systems sure has the leasthoops to jump thru!

There's a reason that when I was offered a job by a microinverter manufacturer I said "Yes"

I've done a number of old-school installs and they are a pain in the rear compared to grabbing an AC PV module, bolting it to the racking and plugging the AC cable into the AC PV module that came before it. When we're testing new firmware I can take the lift to the roof, go over to the module I'm dealing with, use the handy cable disconnect tool, and in a matter of minutes be done with it. That's not possible with any other type of inverter technology. If I could get a lounge chair and umbrella up on the roof, I might even work there.