ILSCO or Polaris Connectors

[jaggedben]

So if I'm using these for tapping an inverter output to a feeder, which are the inputs and which are the outputs?

I'm glad the OP's question was answered affirmatively, that's half the reason I use them.

 

[steve66]

I'm never ceased to be amazed by the nit picking that takes place here. :slaphead::slaphead:

Then you won't believe this, but I got to say it

This is when you are connecting sets of parallel conductors.

If you have 3 conductors (coming from the left) in parallel being connected to 3 conductors (going to the right) in parallel, you have to alternate, left-right-left-right-left-right.

-Jon

Ofcourse, this doesn't matter on a 2 port connector.

And for the Polaris connectors that have terminals on both sides, you just use one side for the input, and the other side for the output. Pretty hard to screw up, unless you really try.

I believe its only the connectors that have all the terminals on one side (all in a single row) where you really need to worry about staggering the inputs and outputs.

 

[GoldDigger]

With an inverter backfeed situation it does not really matter which you call the input and which you call the outputs. You just alternate them either way.


Sent from my XT1585 using Tapatalk

 

[jaggedben]

With an inverter backfeed situation it does not really matter which you call the input and which you call the outputs. You just alternate them either way.

If it's just a three position tap I think it doesn't matter at all. If it's a parallel conductor situation I believe one should do each in sequence and then repeat the sequence. I mostly asked the question just for fun though.

 

[dionysius]

If it's just a three position tap I think it doesn't matter at all. If it's a parallel conductor situation I believe one should do each in sequence and then repeat the sequence. I mostly asked the question just for fun though.

A thinking Electrician will by nature observe the geometry of the target so as not to create a hot spot. This is what I might call good craftsmanship. Kind of analogous to a good mechanic torquing head bolts according to a pattern to minimize a buildup of captured stress at any one point.

 

[kwired]

Consider the three terminal Ilsco shown in the photo above in this thread. Put 200 A into the center lug and take 100 A out off the left right lugs. The current between lugs is "split" and is not greater than 100 A.

Compare that to 200 A in the LEFT lug and a 100 A out of the middle and right lugs. The current between the LEFT lug and the middle lug is 200 A.

The heat created is I squared R, which means the heat in the section of terminal bar with 200 A is FOUR TIMES greater than the 100A section.

The manufacturer is saying"Don't do that!"
Tapatalk

I you have say a two port device rated for 3/0 conductors and connected to a 200 amp circuit all 200 amps will flow through one cross section of the terminal bar on its way from one port to the other. Now split that 200 amp circuit two ways in a same size but three port device - no cross section of the terminal bar will ever carry more then the single supply conductor will deliver to it.

Bump same sized bar up to 4 ports and supply it with parallel 3/0 and 400 amp circuit - now that same cross sectional area of a bar will carry 400 amps at the center point if you put all the supply leads on one end of the bar and the load leads on the other end.

Then you won't believe this, but I got to say it



Ofcourse, this doesn't matter on a 2 port connector.

And for the Polaris connectors that have terminals on both sides, you just use one side for the input, and the other side for the output. Pretty hard to screw up, unless you really try.

I believe its only the connectors that have all the terminals on one side (all in a single row) where you really need to worry about staggering the inputs and outputs.

Terminals are right down the center - some just happen to have access ports in the insulating cover on one side only , some on both sides. You can only use one side or the other at a time on any individual port though.

 

[al hildenbrand]

Now split that 200 amp circuit two ways in a same size but three port device - no cross section of the terminal bar will ever carry more then the single supply conductor will deliver to it.

With respect to the Manufacturer's instruction, your point doesn't have application. My second example is the issue the manufacturer is addressing, in my opinion.

Compare that to 200 A in the LEFT lug and a 100 A out of the middle and right lugs. The current between the LEFT lug and the middle lug is 200 A.

In my example, the terminal bar has two different current densities in it and, as a result, dramatically different I square R loss in one part compared to the other part. I believe the manufacturer is instructing the installer to be mindful of the current distribution along the bar, to minimize temperature differences in the bar.

 

[kwired]

With respect to the Manufacturer's instruction, your point doesn't have application. My second example is the issue the manufacturer is addressing, in my opinion.

In my example, the terminal bar has two different current densities in it and, as a result, dramatically different I square R loss in one part compared to the other part. I believe the manufacturer is instructing the installer to be mindful of the current distribution along the bar, to minimize temperature differences in the bar.

I understand what you are saying, I still don't think it is something that is that critical if you only have one supply conductor, but does warrant paying more attention if you have parallel supply conductors, especially if the conductors are at/near the maximum size the terminals accept.

 

[jaggedben]

A thinking Electrician will by nature observe the geometry of the target so as not to create a hot spot. This is what I might call good craftsmanship. Kind of analogous to a good mechanic torquing head bolts according to a pattern to minimize a buildup of captured stress at any one point.

Well I wonder a bit how many thinking electricians are educated enough about interactive inverters to properly consider that. I'm not knocking electricians as a group, it's just my observation that a minority of people really understand interactive inverters, even among those who work with them everyday. It's a bit different from the typical 'input' and 'output' designation since one connection (utility line side) can be either. As a I said, I asked the question kind of just for fun. Not sure anyone wants to walk through all the scenarios but we can if you want. :lol:

 

[GoldDigger]

Well I wonder a bit how many thinking electricians are educated enough about interactive inverters to properly consider that. I'm not knocking electricians as a group, it's just my observation that a minority of people really understand interactive inverters, even among those who work with them everyday. It's a bit different from the typical 'input' and 'output' designation since one connection (utility line side) can be either. As a I said, I asked the question kind of just for fun. Not sure anyone wants to walk through all the scenarios but we can if you want. :lol:

A very good point about understanding of interactive inverters. There are electricians and inspectors who feel that a tie down is required on a PV backfeed breaker for safety reasons since the detached breaker would have exposed energized leads. That is true for a generator, but not for a GTI.

 

[ggunn]

Terminals are right down the center - some just happen to have access ports in the insulating cover on one side only , some on both sides. You can only use one side or the other at a time on any individual port though.

Polaris also makes blocks with dual terminals on each port so you can make what is effectively a butt splice in each port.