How to inspect? It's new to me!

Status
Not open for further replies.

davedottcom

Senior Member
Is that disconnect rated for DC?
Even with the 'S' jumper, the disconnect still has to be DC rated. Putting the 'S' jumper in an A/C disconnect doesnt necissarily make it D/C rated.

Are you back in PA, yet??
Yes, The Disconnect is rated for DC! :)

Nope, I've been in Canon City, CO & now I'm in Rock Ford CO. I'm inspecting & commissioning these (15) systems.
Doing Expected PV performance VS. Actual PV performance formulas.
Irradiance measurements, Amb. Temps, Cell Temps, Real Time wattage... etc...been here for 2 weeks...FUN! :roll:
I should be back in FL by Thursday, then packing up everything & moving back to PA... ever MORE FUN!!!
I figured since McNabb is gone, it's safe to go back! :grin:
 

cowboyjwc

Moderator
Staff member
Can I assume that this is a larger PV system. Most of the inverters have a built in DC disconnect now.
 
Very good thread. Me being from a small municipality and just now getting our first solar panel system this has taught me a lot!

I've been researching PV systems for a while but this is more hands on type information.

One thing I did for our first installation...residential, was to verify that the structure would support the weight...I know not electrical but I needed to verify, and then notify the fire department of the address in order for them to be aware that just because there was a disconnect for the PV system and a meter that could be pulled that the wires coming from the panels were still energized.

Keep the comments coming...I'm still learning!
 

iwire

Moderator
Staff member
Well they definitely wasted that extra disconnecting means.

I have been to Solectria's factory pretty low tech place for the equipment they make.

Personally I like the units but they up charge to spin the disconnects from facing left and right to facing front. They just do not seem to understand how difficult it is to comply with 110.26 with each disconnect facing left and right. :roll:
 

davedottcom

Senior Member
Well they definitely wasted that extra disconnecting means.

I have been to Solectria's factory pretty low tech place for the equipment they make.

Personally I like the units but they up charge to spin the disconnects from facing left and right to facing front. They just do not seem to understand how difficult it is to comply with 110.26 with each disconnect facing left and right. :roll:
What do you mean wasted the extra disco means?

FYI: out of 15 Inverters, 3 have had to have the "core" replaced within 6 months. :roll:
 

BillK-AZ

Senior Member
How to inspect? It's new to me!

How to inspect? It's new to me!

Some observations/comments:

The DC Disconnect is wired backwards. The fixed pole at the top should be the ungrounded conductor from the PV array.

Most likely the cold Open Circuit Voltage * 1.25 is over 250 volts, the dc conduits must be bonded.

There are copper lay-in lugs designated for direct burial that should be used for all outdoor bonding. UL Listed PV modules should come with specific grounding requirements, an instruction sheet should be provided with each package.

Square-D has a new Technical Note 3110DB0401R0410 that details the UL Listed vs Schneider Electric Certified wiring for photovoltaic systems. The 600V heavy duty switches are no longer UL Listed for a single break. These were often used to disconnect 2 or 3 arrays with one switch. Siemens has a new DC disconnect that is UL Listed for a single break per circuit up to 600 VDC, it uses magnets to control the arcs. The unfused Sq-D disconnects are full 100% rated, so can be sized for short circuit current x 125%. The fused and Schneider Electric Certified wiring must be sized for short circuit current x 156%.

The 2011 Code will require separate DC Disconnects for most situations.
 
Last edited:
Status
Not open for further replies.
Top