How to connect PV system in this CT cabinet

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Solar_OR

Member
Location
Oregon
I have a project that would need to be a line side connection and the only place to accomplish this would be in the CT cabinet at the site. When I opened the CT cabinet though, all of the spaces to land any wires seem to be full. Any thoughts on a way to make space or connect the wires for the PV system?

Thank you for your help
 

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electrofelon

electrofelon

Senior Member
Location
Cherry Valley NY, Seattle, WA
Solar_OR said:
I have a project that would need to be a line side connection and the only place to accomplish this would be in the CT cabinet at the site. When I opened the CT cabinet though, all of the spaces to land any wires seem to be full. Any thoughts on a way to make space or connect the wires for the PV system?

Thank you for your help
Click to expand...

A couple questions back at you: Are those connectors rated for two cables? You may want to verify that. Also, it looks like you have two sets of service entrance conductors, is that correct?

My first thought would be one of these multi port connector blocks. If you do have multi sets of service entrance conductors, you may not need to tap all 6 conductors. Another option may be to bolt an additional lug on to the existing load side studs, although the inspector may not like it citing 110.3
 

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ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Consulting Electrical Engineer - Photovoltaic Systems
Solar_OR said:
I have a project that would need to be a line side connection and the only place to accomplish this would be in the CT cabinet at the site. When I opened the CT cabinet though, all of the spaces to land any wires seem to be full. Any thoughts on a way to make space or connect the wires for the PV system?

Thank you for your help
Click to expand...
The AHJ's around here will not allow you to interconnect in their CT can. They get bent out of shape if you even open one up to look at what's inside.
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
ggunn said:
The AHJ's around here will not allow you to interconnect in their CT can. They get bent out of shape if you even open one up to look at what's inside.
Click to expand...

Much the same here.

Here we would provide and install a CT can like that for the power company but once they install their CTs any access to it is limited and any changes would have to be approved by the power company.
 
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pv_n00b

Senior Member
Location
CA, USA
Assuming it's the utility's metering it's best not to put anything in the CT can. Were there utility seals on the can?
 
Smart $

Smart $

Esteemed Member
Location
Ohio
electrofelon said:
... Another option may be to bolt an additional lug on to the existing load side studs, although the inspector may not like it citing 110.3
Click to expand...
This is the route I'd go... that is, if silly rules do not impede.

I'd use a compression lug on my conductors and land directly on the studs.
 
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pv_n00b

Senior Member
Location
CA, USA
Smart $ said:
I'd use a compression lug on my conductors and land directly on the studs.
Click to expand...

But then again that silly 110.3 gets in the way. Sometimes safety is so limiting. :happyno:

It's hard to tell if the conductors on the load side of the CTs are parallel or single circuits. Maybe there is a chance to tap conductors there.
 
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Solar_OR

Member
Location
Oregon
Thank you for all the input. To answer a few of the questions...

- The load side terminals are rated for two conductors.
- There are two sets of service entrance conductors, and the utility is actually adding a third to compensate for the potential backfeed. That is how I got the picture when they opened to see how much work they were getting into.
- I have asked and gotten approval from the utility to land in the CT cabinet. I am just not sure how to accomplish that at this point.

I need to offset the meter so tapping the service conductors will do me no good. I thought of possibly bolting on one of those stacked terminal lugs if it will stick out far enough, but then I am afraid of blocking the set screw for the existing lugs. Were you thinking I could use a Polaris connector to combine some of the existing wires and free up space?
 
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jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
Solar_OR said:
Thank you for all the input. To answer a few of the questions...

- The load side terminals are rated for two conductors.
- There are two sets of service entrance conductors, and the utility is actually adding a third to compensate for the potential backfeed. That is how I got the picture when they opened to see how much work they were getting into.
- I have asked and gotten approval from the utility to land in the CT cabinet. I am just not sure how to accomplish that at this point.

I need to offset the meter so tapping the service conductors will do me no good. I thought of possibly bolting on one of those stacked terminal lugs if it will stick out far enough, but then I am afraid of blocking the set screw for the existing lugs. Were you thinking I could use a Polaris connector to combine some of the existing wires and free up space?
Click to expand...

I believe electrofelon was suggesting using a multiple-terminal Polaris type block to tap the (evidently) paralleled conductors on the load side, as just discussed in this recent thread.

I think we're all a little curious what's going on with those load side conductors. Are they all paralleled conductors for one circuit or are there multiple circuits heading to different disconnecting means? It would make a difference to how many of them you'd have to tap and how difficult an option that might be. And there might be ampacity considerations too.
 
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Solar_OR

Member
Location
Oregon
The conductors all go to these various disconnects which are feeding different areas of the building. They are all 200A disconnects and the PV system is 800A so tapping the conductors I don't think would work. Combining some of the conductors for the disconnects may work to free up a spot to land the PV. Another issue is that I would have 2 sets of 600 MCM for the PV. It all seems too crowded.
 

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jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
Solar_OR said:
The conductors all go to these various disconnects which are feeding different areas of the building. They are all 200A disconnects and the PV system is 800A so tapping the conductors I don't think would work. Combining some of the conductors for the disconnects may work to free up a spot to land the PV. Another issue is that I would have 2 sets of 600 MCM for the PV. It all seems too crowded.
Click to expand...

I think tapping them could work just fine. You just have to tap them all together with a block like we've referred to. If each conductor is rated 200A, then you need to tap four of them. As far as I can see. I suppose practicality might be an issue, depending on what size conductors you wanted to use for your PV output. But I don't see it as code issue.
 
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shortcircuit2

Senior Member
Location
South of Bawstin
Solar_OR said:
I have a project that would need to be a line side connection and the only place to accomplish this would be in the CT cabinet at the site. When I opened the CT cabinet though, all of the spaces to land any wires seem to be full. Any thoughts on a way to make space or connect the wires for the PV system?

Thank you for your help
Click to expand...

What is feeding that CT Cabinet? Is that 2 sets of 350 MCM AL? What size transformer?
 
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shortcircuit2

Senior Member
Location
South of Bawstin
Smart $

Smart $

Esteemed Member
Location
Ohio
Solar_OR said:
... I thought of possibly bolting on one of those stacked terminal lugs if it will stick out far enough, but then I am afraid of blocking the set screw for the existing lugs. ...
Click to expand...
94360-ProductImageURL.jpg


Two-hole versions are also available.

You could go this route...

...but they are hard to come by.
 
A

Anode

Member
Location
Washington, USA
Solar_OR said:
The conductors all go to these various disconnects which are feeding different areas of the building. They are all 200A disconnects and the PV system is 800A so tapping the conductors I don't think would work. Combining some of the conductors for the disconnects may work to free up a spot to land the PV. Another issue is that I would have 2 sets of 600 MCM for the PV. It all seems too crowded.
Click to expand...

Yeah, agreed with most of the other responses here. Our POCO's would not allow tapping in the CT can.

Also agree on the tap method with insulated tap connectors, probably easy to achieve in those wireways adjacent to your utility CT can. There are many varieties to choose from, should make the work easy enough in that space, unless I am missing something...
 
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bsmith8691

Member
Location
Ellington, CT
I would have to agree with Anode......a wire way with sufficient fill would make a much cleaner install. Personally, I would take it a step further and label the wires as to which disconnect they went to .

Sent from my XT1254 using Tapatalk
 
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ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Consulting Electrical Engineer - Photovoltaic Systems
How large is the PV system compared with the panels fed from the bus in the CT can? It may be possible to establish a point of interconnection on the supply side of one of the panels. If there are multiple inverters it may be possible to connect to multiple panels on their supply sides.
 
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