Sizing the fitting for a compression splice?

[SpiderDave]

Okay. I'm hooking up a transfer switch & generator which has grossly taken too long due to small hurdles along the way, but I'm almost done. It's all legit with a city permit, etc. I need to further extend the 4/0 wire into the transfer switch panel, becasue it's too short to reach the breaker lugs. I explored the option of tearing out the interior wall, moving everything over and gaining some slack to keep it all one piece, but it's a no-go. So I chose a splice and confirmed with the city, that this is permitted.

I've got a hydraulic compression crimper for the job. My plan's to use a compression crimp like the one shown below, extend the wire, insulate with marine grade shrink wrap, abrasion tape over that for good measure and away we go.

But I'm having a hard time finding 4/0 crimps without a lengthy wait time and most are out of stock. I do see a more common 250mcm size, which is like 8.9% larger than the 4/0 AWG. This's actually what an electrician friend originally suggested I use. I'm not sure why and he's not available to ask. Myself, I prefer to have a tight fit when it comes to my main line so the crimp contact is more effective and less to shrink inward. I can cut the line so it's clean and not expanded, so would it still need the extra room of a 250mcm fitting? Is the larger size a better choice?

I was hoping for opinions on whether I should wait it out for the 4/0 crimp or get the 250mcm all the same becasue it's not enough to make a difference and might need to room to work with the cable? For a smaller wire, I wouldn't be very concerned, but being our power line to the breaker panel, I want to make sure. Any advantages to using a slightly larger size? Or stick to exact? Any advice or opinions would be great if you can spare it.

Thanks for reading and have a good one.

 

[wyliesdiesels]

why not skip all that hassle and just use insulated polaris connectors?

Polaris 500 MCM - 4 AWG Bagged Insulated In-Line Splice, Black ISR-500B - The Home Depot

Enhance the look of your space by using this Polaris Bagged Insulated InLine Splice Black

www.homedepot.com

 

[mm08822]

What does it take to replace the 4/0 with new mtl to eliminate all splices?

The sleeve below is only rated for copper conductors.

 

[SpiderDave]

why not skip all that hassle and just use insulated polaris connectors?

Polaris 500 MCM - 4 AWG Bagged Insulated In-Line Splice, Black ISR-500B - The Home Depot

Enhance the look of your space by using this Polaris Bagged Insulated InLine Splice Black

www.homedepot.com

Thanks! That was my first choice. But I was told by an electrician (the big debate of compression vs mechanical splicing) who does a lot of larger AWG work that the crimp is more trustworthy and a more even hold all around without crushing and spreading the wiring apart. That the 360* inward compression forces the connection tighter as the strands are compacted with little to no air between them becoming more one like a rod than smashed apart. (in short) Personally, I don't see why I'd need that much grip on a floating splice but the compression contact and I understand. I think there was mention of less chance of resistance, but by that point I was overloading on info. Plus, having the hydraulic compression tool kinda makes that easier to sell. Ha!

I haven't taken the mechanical connectors like you suggested off the table yet. Starting to look a whole lot easier.

also need 4/0awg rather than 4awg, but maybe that wasn't the point you were showing me.

 

[nadogail]

Have you tried a supply house in Spokane?

As I recall Spokane was not all that far from Lewiston.

 

[SpiderDave]

What does it take to replace the 4/0 with new mtl to eliminate all splices?

I don't understand the question but thanks for the snapshot. I saw that one, but it's copper and I was trying to stay with aluminum same as the wiring, as not to mix metals. Now that I've done more research, I noticed the aluminum spices do say for both aluminum and copper - dual. I guess I just didn't make that connection until about 20 seconds ago.

So is it best to stick with 4/0 size crimp or a little bigger? Or are the 4/0 crimps already a slightly larger fit to accommodate some expansion from cutting? I am going to go check into this one you showing right now. Most places say 5-7 business days to ship. thank you.

 

[SpiderDave]

Have you tried a supply house in Spokane?

As I recall Spokane was not all that far from Lewiston.

Haven't found any, but will check anyway. thanks! Most have been on the far East side. And you're right, it's close. Though I've moved since and still not that much further. Need to update my location.

 

[wyliesdiesels]

Thanks! That was my first choice. But I was told by an electrician (the big debate of compression vs mechanical splicing) who does a lot of larger AWG work that the crimp is more trustworthy and a more even hold all around without crushing and spreading the wiring apart. That the 360* inward compression forces the connection tighter as the strands are compacted with little to no air between them becoming more one like a rod than smashed apart. (in short) Personally, I don't see why I'd need that much grip on a floating splice but the compression contact and I understand. I think there was mention of less chance of resistance, but by that point I was overloading on info. Plus, having the hydraulic compression tool kinda makes that easier to sell. Ha!

I haven't taken the mechanical connectors like you suggested off the table yet. Starting to look a whole lot easier.

I wonder if he has actual reference papers to back all that up or is it just his personal observations

 

[SpiderDave]

Maybe I'm not looking in the right places, but I don't see any 4/0 mechanical in-line or single side connectors. They're all 250mcm, so that takes me back to my question of finding an exact fit or bigger?

 

[mm08822]

I don't understand the question but thanks for the snapshot. I saw that one, but it's copper and I was trying to stay with aluminum same as the wiring, as not to mix metals. Now that I've done more research, I noticed the aluminum spices do say for both aluminum and copper - dual. I guess I just didn't make that connection until about 20 seconds ago.

So is it best to stick with 4/0 size crimp or a little bigger? Or are the 4/0 crimps already a slightly larger fit to accommodate some expansion from cutting? I am going to go check into this one you showing right now. Most places say 5-7 business days to ship. thank you.

Can you replace the conductors that are too short with longer conductors to eliminate all splices? e.g. - between meter and xfer switch cb?

If you are splicing 4/0, you use 4/0 barrels. DO NOT UPSIZE. Aluminum conductors will require Cu-AL rated barrels.

If the ends are out of round then use pliers to round it out. Maybe even a file to knock any burrs off the strand ends, but generally not needed.

Make sure you use the proper crimp dies.

Below is for Al 4/0.....

 

[SpiderDave]

I wonder if he has actual reference papers to back all that up or is it just his personal observations

Mostly personal preference I'd guess. As a metal fab guy myself the idea of inward circular pressure for contact, made sense. But with all the mechanical connections in 3 panels and everywhere else before and after, I'm not sure a compression splice if it is that good, really tips the scales that much. That's just my opinion, I wouldn't know enough to debate it.

 

[alfredeneuman]

ILSCO Aluminum Splicer/Reducer, Dual Rated, Conductor Range 250-6, Tin Plated SPA-250-EC - The Home Depot

Add a wonderful appearance to your decor with ILSCO 2/0-Aluminum Splicer Reducer Dual Rated Conductor Range Plated

www.homedepot.com

Cover it well with tape Available at HD

 

[mike93lx]

Polaris connectors are solid and completely acceptable. If you install it right, it will work well for a long time.

How are your wires connected to breakers and the lugs on your meter? It's the same style...no crimps.

It's fine. Keep it simple and get the project done

 

[SpiderDave]

Polaris connectors are solid and completely acceptable. If you install it right, it will work well for a long time.

How are your wires connected to breakers and the lugs on your meter? It's the same style...no crimps.

It's fine. Keep it simple and get the project done

yep, all lug style mechanical connections throughout.

 

[mike93lx]

yep, all lug style mechanical connections throughout.

So git r done and work on the next project

 

[SpiderDave]

Can you replace the conductors that are too short with longer conductors to eliminate all splices? e.g. - between meter and xfer switch cb?

If you are splicing 4/0, you use 4/0 barrels. DO NOT UPSIZE. Aluminum conductors will require Cu-AL rated barrels.

If the ends are out of round then use pliers to round it out. Maybe even a file to knock any burrs off the strand ends, but generally not needed.

Make sure you use the proper crimp dies.

Below is for Al 4/0.....

@mm0822, wish I could replace it and have one piece. That was one of my electrician buddies many good ideas, and a sound one at that. But not an option unfortunately. The lead that needs extending is between the last breaker of the service panel and the panel on the other side of the house. The transfer switch panel goes between / interrupts that circuit. Too much involved in replacing that one. Good idea though.

And hey, thanks alot for that screenshot, these are perfect. That's in California too, so only 2-3 days to get here and they ship right away. I did look for the insulated mechanical spilcer's - the easiest & simplest answers. Maybe I didn't look hard enough being so glazed over with this, but I didn't find any specific to 2/0 AWG wire. I'm more comfortable with an exact fit when it come to compression, be it hydraulic or by allen wrench. So I'm buying these tonight!

Mike931x's right, git'er done and on to the project! I was over thinking it a bit, but it was a big deal, so I kinda had to all things considered. Either would've worked fine, so I'm not knockin the others at all. But I got to thinking (uh oh!), with limited room in the main panel (right side only) and the mechanical spilcer's being a little fatter, I may need the room when doubling back with all that wire after routing through the transfer switch. Plus getting the proper size this time put a lot of uncertainty aside.

Couldn't have done it without you guys giving me something to chew on here, so thank you all! Hope to repay the favor someday.

P.S. I'll post a pic when it's done, just for the heck of it so people can see what I was talking about.

 

[mike93lx]

Stuff like your breakers aren't sized specifically to the wire either and regarding the concern of Doubling back wire, Polaris connectors are available in a bunch of configurations that can make packaging a lot easier. I know you have a path forward with the crimp, just mentioning so if it comes up again, you have something else to consider

 

[Bert_]

The Polaris connectors and most any lug will have a fairly large range of sizes it will accept. Probably #2-250mcm and that means anything in between.

I would probably use a crimp but that's mostly because I have the tool and the crimps are way cheaper. The crimp is better but you really don't need it to be better. This should be a common crimp, I have a box of them at the shop. A but splice crimp is only going to accept one or Maybe two sizes of wire. H taps will take a wider range

 

[SpiderDave]

The Polaris connectors and most any lug will have a fairly large range of sizes it will accept. Probably #2-250mcm and that means anything in between.

I would probably use a crimp but that's mostly because I have the tool and the crimps are way cheaper. The crimp is better but you really don't need it to be better. This should be a common crimp, I have a box of them at the shop. A but splice crimp is only going to accept one or Maybe two sizes of wire. H taps will take a wider range

I agree. There were some issues I didn't think worth mentioning that I was responding to and caused the dilemma for myself. Mostly by the inspector's ambiguous comments. When I asked what he meant, that was it, my dime was up. I'm not a fan of playing guessing games when I'm trying to do right. But I feel confident about it now.

It wasn't an easy choice, liking both. After being hung up on it for days on end, it just feels good to make one and move forward. That's where this place comes in handy, as most times I get more out of people's opinions whether we agree or not, than I do from the internet. Grateful for all the help!