Tapping on an instrument wire

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electrofelon

electrofelon

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Cherry Valley NY, Seattle, WA
We are coming up with a common situation with our PV systems where we need to tap on a small wire, just 14 or 12 copper for voltage reference and power for an energy monitor on to the service conductors. The way it almost always works out for us, because we specialize in ground mounts and the way I like to make the interconnection, we have a pull box located on a pedestal under or next to the utility meter. There's no disconnect, panel board or other equipment at the pedestal besides the meter and the box. The conductors in the box are typically 4/0 or 250 aluminum and have connections with h taps. So how to tap on a 12 copper onto these aluminum service conductors? Just hoping maybe there's some slick easy cheap way I haven't thought of or don't know about 🤔. It seems like someone must make like a little clamp like mini insulation piercing thing with a stud or a screw for a ring terminal? Don't utilities have need for such a thing? I tried googling various things but couldn't come up with anything. It's tempting to just put a piece of #12 CU in the h-tap before crimping, and I'm 99.3% certain that wouldn't result in a compromised connection or a failure, but I'm still having trouble bringing myself to do that. Split bolt seems like Overkill and not rated for that smaller wire anyway. Polaris type connectors usually only go down to number six at that size, and granted I could wire nut a 6 tail to a 12 for the monitor, but I don't really want to use Polaris connectors, they're spendy and I love my h-taps. Any other ideas?
 
zbang said:
Something like this?
"KUP-L-Tap Insulation Piercing Copper Connector, Dual Rated, Main Conductor Range 4/0-4, Tap Range 6-14, Tin Plated, UL, CSA"

There are more sizes (https://www.ilsco.com/Ilsco/ccrz__ProductList?categoryId=a0Kf400000G17g0EAB&cclcl=en_US)
Click to expand...
No, I guess i didnt state it, but they suffer from the same issue as a polaris connector: way overkill, spendy, and dont go down small enough. I just need something small, this thing probably draws 20 milliamps.

Another idea I thought of is drilling and tapping a 8-32 hole in the center of the H-tap for a ring terminal.

Oh I found this too, insulation piercing but more inline with small and cheap......not listed however.
www.ekmmetering.com

EKM Insulation Piercing Connector

EKM-IPC Insulation Piercing Connector 4/0 wire to 14 AWG wire ~section 2~ Function: Tap a small wire off of a large wire Primary Wire Size: #6 to 4/0 wire Secondary Wire Size: 14 to 10 AWG Model: EKM-IPC A convenient and fast way to safely and securely tap off of an existing line. You can tap...
www.ekmmetering.com www.ekmmetering.com
 
I've seen the conductor with a small window of insulation skinned away, a single strand pulled away, and a small conductor connected to it with a small U-bolt.
 
I suspect none of the inexpensive solutions will be listed or they'll void any listing the device had.

BTW, the Ilsco ones go down to 14g and are under $20 each - consider that the cost of being listed and easy to install. (Sure you could mod the H-tap, but you'd still have to drill/tap that three times and crimp on three rings; might save a few $ but it's probably under $50.)
 
We use Ilsco's. They have versions that are designed only for metering and instrument taps. Here's a #12 tapped to what i believe to be a 600 kcmil. The second photo is a smaller version (500 kcmil) of the same type of tap.

CoGen Taps 001.jpgKupler Metering Only.jpg
 
electrofelon said:
It's tempting to just put a piece of #12 CU in the h-tap before crimping, and I'm 99.3% certain that wouldn't result in a compromised connection or a failure, but I'm still having trouble bringing myself to do that.
Click to expand...

I'd write to the manufacturer of the H taos that you use, pointing out the need. Maybe they could be talked into getting 'add a metering conductor parallel to the main conductor under a single crimp' listed.
 
electrofelon said:
We are coming up with a common situation with our PV systems where we need to tap on a small wire, just 14 or 12 copper for voltage reference and power for an energy monitor on to the service conductors. The way it almost always works out for us, because we specialize in ground mounts and the way I like to make the interconnection, we have a pull box located on a pedestal under or next to the utility meter. There's no disconnect, panel board or other equipment at the pedestal besides the meter and the box. The conductors in the box are typically 4/0 or 250 aluminum and have connections with h taps. So how to tap on a 12 copper onto these aluminum service conductors? Just hoping maybe there's some slick easy cheap way I haven't thought of or don't know about 🤔. It seems like someone must make like a little clamp like mini insulation piercing thing with a stud or a screw for a ring terminal? Don't utilities have need for such a thing? I tried googling various things but couldn't come up with anything. It's tempting to just put a piece of #12 CU in the h-tap before crimping, and I'm 99.3% certain that wouldn't result in a compromised connection or a failure, but I'm still having trouble bringing myself to do that. Split bolt seems like Overkill and not rated for that smaller wire anyway. Polaris type connectors usually only go down to number six at that size, and granted I could wire nut a 6 tail to a 12 for the monitor, but I don't really want to use Polaris connectors, they're spendy and I love my h-taps. Any other ideas?
Click to expand...
While I know it technically violates the lug's listing, I've used long bootlace ferrules on #12 wire, and placed it behind the main conductor under the breaker lug's setscrew:

www.mcmaster.com

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.
www.mcmaster.com www.mcmaster.com

Especially for larger conductors, the ferruled wire is pretty much the same size as the conductor strands too. And yes, I ran it by the inspector before I did it, and he was OK with it. All he asked for was a good dug test (that he witnessed) to ensure the small conductor was secure, and to zip tie the small conductor to the main conductor near the termination, for strain relief.

Winnie's suggestion of asking your H-tap manufacturer is a good idea too.




SceneryDriver
 
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