Buchanan Splice Caps and other novel splicing methods.

hwy17 · Apr 11, 2024

My PV run needs some splices and there's nothing I can do about it. It needs PV wire to THHN splices, and I'd rather not keep dancing around making more splices in the THHN run. There should not be a need to be nervous about a splice of under 30 amps.

1. Wagos - I trust them for AC splices of 15, 20, 30 amps. Why shouldn't I trust them for a PV splice? Only logical reason would be that a PV splice is expected to be heavily loaded. But heavily loaded at 16 amps only.

2. Wire nuts. I hate wire nutting stranded wire, I won't do it.

3. Buchanan Splices? So apparently these are a listed 600v splice method. Home Depot carries the crimps themselves but not the caps, I'm guessing because they are commonly used for irreversible ground wire splices. But they are listed for live wires with a hard to find insulator cap.

4. Anyone got any other idea for listed wire splice methods that you'd be twice as confident in as a wire nut or wago?

Gttnsun · Apr 11, 2024

Polaris connectors?

hwy17 · Apr 11, 2024

Gttnsun said:
Polaris connectors?

Yup, those are worth considering. $15 per connection is pretty steep of course though, for 10-14awg.

Gttnsun · Apr 11, 2024

hwy17 said:
Yup, those are worth considering. $15 per connection is pretty steep of course though, for 10-14awg.

They are expensive, if you have alot of connections it probably doesn't make sense.

Hedges · Apr 11, 2024

I've been using "Ideal" set-screw wire nuts. a.k.a. Marrettes

hwy17 · Apr 11, 2024

Hedges said:
I've been using "Ideal" set-screw wire nuts. a.k.a. Marrettes

Oh never seen those before. Seems like the model 11 is 600v rated (model 10 300v). I don't love the presumably brass fitting as much as the Buchanan copper, but non permanent is a plus.

Hard to find like the Buchanan but half the price, about $1 each.

hwy17 · Apr 11, 2024

Gardner Bender 20-123 or 75-126
butt splices are 600v rated. But it would feel so wrong to see in a box.

hwy17 · Apr 11, 2024

Gttnsun said:
They are expensive, if you have alot of connections it probably doesn't make sense.

Loading…

www.amazon.com

Available as cheap as $10 a piece. I didn't expect that. Compared to spending $120 on a kit to start making Buchanan splices, maybe hard to argue against this. Probably hard to stuff these in a 1 or 2 gang box though.

hwy17 · Apr 11, 2024

Bit of an industry endorsement of the Buchanan splice here, although I think this is for micro inverter AC wire.

wpns · Apr 12, 2024

Is MC4 an option?

Hedges · Apr 12, 2024

hwy17 said:
Oh never seen those before. Seems like the model 11 is 600v rated (model 10 300v). I don't love the presumably brass fitting as much as the Buchanan copper, but non permanent is a plus.

Hard to find like the Buchanan but half the price, about $1 each.

It is brass, but current path should be wire to wire.

Sold by Home Depot, but not a stocked item in the store.

IDEAL Model 11 Set-Screw Wire Connector (100 per Box) 30-211 - The Home Depot

Ideals set screw wire connectors ensure a vibration-resistant splice, perfect for applications near motors or other vibration. The solid brass sleeve insert allows wire ranges 22 AWG - 10 AWG. Each package

www.homedepot.com

I've been buying on eBay.

Model 10 cheaper

Ideal 30-210 Set-Screw Wire Connector, Model 10, 22-10 AWG, 100/box Wire Nuts | eBay

<p dir="ltr" style="margin-top:0; margin-bottom:0;">This is a full box and comes as pictured. It does not have the little yellow plastic holder that generally comes with these. Please see photos for full description and condition and ask any questions before purchase. No returns. </p>

www.ebay.com

Model 11 more expensive

Ideal 30-211 30-211 Set-Screw Wire Connector, Model 11, 22-10 AWG, 100/box | eBay

Price is for 100 units. IDEAL INDUSTRIES, INC has made its mark by developing the iconic products and practical technology demanded by critical industries like data communications, aerospace, electrical, wire processing, automotive, construction and more.

www.ebay.com

hwy17 · Apr 12, 2024

wpns said:
Is MC4 an option?

Well I could professionalize my THHN to PV transition a bit with a combiner box or something that handles this a different way than an insulated splice stuffed in a box, but then in the intermediate sections I'd still be trying to avoid them. My panel to charge controller run is 250 ft with 3 different sections. So that would mean I couldn't even get two contiguous runs done with my 500ft spools of thhn that I already used 16ft of short scraps from.

I'm more interested in overcoming the limitation here, a reliable and compact 20 amp splice should not be out of reach. I'd like to be able to splice anywhere I want and not worry about it.

littleharbor2 · Apr 12, 2024

Would split bolts be an option?

hwy17 · Apr 12, 2024

Panduit Stronghold seems to be their line of UL Listed butt splices.

Under 50 cents a piece, maybe a technically perfectly legal wiring method.

@timselectric Can I put butt splices in outdoor above ground weatherproof boxes for PV voltage DC or would that be too dorky?

hwy17 · Apr 12, 2024

littleharbor2 said:
Would split bolts be an option?

Yes, thought about that, they are. But they're usually larger than 10 or 12 awg, and then you're stuck taping them afterwards. Tape doesn't sit right with me. I know it's legal but at the very least it will be sticky if you have to get back in there later.

hwy17 · Apr 12, 2024

Buchanans might beat butts in that they're a little more compact, and you get to see the inside of the crimp before you put the insulator on.

On the other hand, Buchanan's don't have as much crimp to wire surface and are relying on a wire to wire current flow. While butt splices can have a nice flattened wire contact.

hwy17 · Apr 12, 2024

Hedges said:
It is brass, but current path should be wire to wire.

Agreed and I would believe in that for splicing two clean straight solid wires. But for 12 awg stranded, my mind just imagines the set screw twisting them up or a couple hairs ending up straddling the screw instead of compressed by it.

Is the screw wider than the barrel of the connector so they can't end up either side of it?

wpns · Apr 12, 2024

hwy17 said:
Can I put butt splices in outdoor above ground weatherproof boxes for PV voltage DC or would that be too dorky?

How about waterproof heat-shrink marine butt splices? Regular ones might technically work, but high voltage DC outside wouldn’t sit right with me.

hwy17 · Apr 12, 2024

wpns said:
How about waterproof heat-shrink marine butt splices? Regular ones might technically work, but high voltage DC outside wouldn’t sit right with me.

I haven't looked thoroughly, but I believe those are not usually both 600v rated and UL listed/rated. In my case these are for inside a weatherproof box like this with a gasket sealed cover plate:

timselectric · Apr 12, 2024

hwy17 said:
Panduit Stronghold seems to be their line of UL Listed butt splices.

View attachment 208889

Under 50 cents a piece, maybe a technically perfectly legal wiring method.

@timselectric Can I put butt splices in outdoor above ground weatherproof boxes for PV voltage DC or would that be too dorky?

Maybe dorky, but electrically fine.

Buchanan Splice Caps and other novel splicing methods.

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