8 Gauge to 10 Gauge Wire Reducer?

[eric@psmnv]

The wires coming from our panels to our charge controller look a lot like coax on the outside. They are .25 in. (6.6 mm) in diameter, and inside are 19 separate copper conductors, twisted together, and surrounded by a single black jacket. The internal bundle of conductors is .17 in. (4.6 mm) in diameter, which is about the same as an 8 ga. wire. The bundle is too big to fit into the openings on the charge controller. I need some kind of wire reducer/adapter, to take the 8 ga. equivalent bundle down to about 10 ga. to fit into the charge controller. Replacing the wires is not an option. Anybody know of something that would work?

[bob-n]

That sounds like standard stranded wire.

You can get connector blocks that accept pairs of wires and connect them together. For example, Marathon 985-GP accepts from 4 gauge to 18 gauge and comes a few different models. The smallest is for two pairs 985-GP-02. 985-GP-03 is for 3 pairs, etc. Search Amazon or Newark Electronics for Marathon 985-GP. You put the #8 wire in one end and the #10 or #12 in the other, and tighten the screws to the factory specified torque. Simple and fast. There are other Marathon products that would also work, but this is probably the simplest choice. Here's a photo of the 985-GP-03, courtesy Amazon:
71iIyXBIopL._SL1500_.jpg

Another choice is to get "Pin Terminals". These are crimp devices which go around the wire and have a straight pin on the end of a smaller diameter. For example Digikey, Allied, Newark and Mouser sell TE Connectivity / AMP 180599 pin terminals. The advantage of these is that they're small and cheap. Unfortunately, to use these, you either need a crimp tool or you need to be extremely good with improvising. Search for "TE AMP 180599".
inhouse_180599_t.jpg

With any approach, you need to make sure that the connection is both secure and safe from fingers, dropped tools, etc.

[Mike90250]

If you don't have the right factory crimper, don't improvise a way to crimp the pin terminals. you will regret it if it causes a fire. You need a 5 ton hydraulic crimper, not a $4 automotive crimper.

Solder is a NO-NO for high current applications. It can melt away if the connection heats up, and can wick up the wire strands and cause a hidden break under the insulation with only a little wire movement.

Or use a splice block

https://lugsdirect.com/splicer-wire-lugs.htm

or a split bolt (with the proper rating)

https://www.homedepot.com/p/RACO-8-4-STR-Split-Bolt-5-Pack-KS20BAG1R/202944356

or

https://www.elecdirect.com/split-bolts-grounding-products/split-bolt-connectors

I now use copper loaded (or silver loaded) electrical grease at all connections to prevent mishaps. And there is a skill to using barely enough to provide results, not a terrible gloppy mess.

https://www.mcmaster.com/conductive-grease

[eric@psmnv]

I love this forum. Knowledgable folks are so willing to help.

I had considered pin terminals and I like that idea best, but when you look for pin terminals on Amazon they don't show an amperage rating. so I'm not sure if they're safe. Also, my crimper is a $20 hardware store special that I got for making coax cables for a cell phone booster. Do I really need an expensive hydrolic crimper?

[bob-n]

Eric,

As Mike said, the correct crimp tool is the only dependable way to go. It doesn't have to by hydraulic, but it needs the correct size and shape jaws. If your tool has the right jaws and you use it carefully, you will probably succeed. But why risk it?

The splice blocks from Lugs Direct or Marathon are UL rated and inexpensive. They are also easy to rework. The Marathon block also has insulation. You won't regret either choice.

Mike,

I'd like to learn more about electrical grease. There's so much hype on grease in discussion groups but I haven't found anything authoritative on using it for terminals. Can you share your experiences and any good technical links?

Thank you.

[eric@psmnv]

Could you link me to an appropriate crimp tool?

[bob-n]

You can find that on the TE Connectivity / AMP website. https://www.te.com/usa-en/product-180599.html

[Mike90250]

I use a $50, 8 ton rated tool from ebay. I also spent 35 years in aerospace using $2,000 crimpers that were calibrated every 6 months and I know what a good crimp is.
A good crimp cold welds the wires to the shell, and leaves an uncrimped portion of the shell as a strain relief for the wire. The wire will break before it pulls out of the shell.

There are several kinds of electrical grease, some are insulative, some are conductive. They come in silver, copper and carbon. Silver is used at power plants and substations to grease the double bolt threads and connection interfaces. The lugs are the size of your leg. Giant stuff. I used that till it ran out, I now have the copper from McMaster Carr. The Carbon I have no experience with and the numbers show it's not as conductive as silver or copper. But carbon is this years buzzword, so it must be good.
this is hands on learning, too little and it's useless, too much and it runs out and causes a short in 2 years.
Safest is the No-Oxid, warm the tub till it's liquid and dip the stripped wire in, then torque it down in the terminal. I've not used it for crimping, only have used the copper for crimping copper wire, you don't mix metals.

The insulated splice blocks are the easiest way, with a dab of no-ox in the joint to protect the wires
https://www.sanchem.com/electrical-c...lubricant.html NO-OX-ID "A-Special" is the stuff you melt and dip the wire into before torque. and you MUST use a torque tool. I use a gunsmiths tool. Too loose and the wires loosen and overheat from poor contact. Too tight, you strip threads or crush/cut strands and again, overheat.

[eric@psmnv]

You can find that on the TE Connectivity / AMP website. https://www.te.com/usa-en/product-180599.html

Yikes, $1100 for a tool that squeezes a metal pin terminal onto a bundle of copper wires. That's way out of my league. If it's really that risky to use a consumer-grade crimper, then I guess the $2 splice blocks are the way to go.

[Ampster]

Yikes, $1100 for a tool that squeezes a metal pin terminal onto a bundle of copper wires. That's way out of my league. If it's really that risky to use a consumer-grade crimper, then I guess the $2 splice blocks are the way to go.

I bought a cheap Chinese hydraulic crimper that does everything from 4/0 to 12 Ga wire. Well worth the money, especially for the big Amp connections. It was less than $50.

[eric@psmnv]

I use a $50, 8 ton rated tool from ebay. I also spent 35 years in aerospace using $2,000 crimpers that were calibrated every 6 months and I know what a good crimp is.
A good crimp cold welds the wires to the shell, and leaves an uncrimped portion of the shell as a strain relief for the wire. The wire will break before it pulls out of the shell.

There are several kinds of electrical grease, some are insulative, some are conductive. They come in silver, copper and carbon. Silver is used at power plants and substations to grease the double bolt threads and connection interfaces. The lugs are the size of your leg. Giant stuff. I used that till it ran out, I now have the copper from McMaster Carr. The Carbon I have no experience with and the numbers show it's not as conductive as silver or copper. But carbon is this years buzzword, so it must be good.
this is hands on learning, too little and it's useless, too much and it runs out and causes a short in 2 years.
Safest is the No-Oxid, warm the tub till it's liquid and dip the stripped wire in, then torque it down in the terminal. I've not used it for crimping, only have used the copper for crimping copper wire, you don't mix metals.

The insulated splice blocks are the easiest way, with a dab of no-ox in the joint to protect the wires
https://www.sanchem.com/electrical-c...lubricant.html NO-OX-ID "A-Special" is the stuff you melt and dip the wire into before torque. and you MUST use a torque tool. I use a gunsmiths tool. Too loose and the wires loosen and overheat from poor contact. Too tight, you strip threads or crush/cut strands and again, overheat.

If the binding of the pin-terminal to the wire bundle is that critical, it makes me wonder about where the bundle plugs into the charge controller. The wire bundle is just jammed into a square hole, and a simple Phillips-head screw inside the controller gets turned, which narrows the metal contacts inside (flat metal surfaces) and clamps down on the bundle. If that works okay at the connection to the charge controller, I wonder why the pin terminal just an inch or so away needs an industrial-quality crimp job.

If you wouldn't mind linking me to a tool like yours, that would be helpful.

[eric@psmnv]

I bought a cheap Chinese hydraulic crimper that does everything from 4/0 to 12 Ga wire. Well worth the money, especially for the big Amp connections. It was less than $50.

Can you send me a link to one like you bought?

[Ampster]

Check to make sure it has the die sizes you need. I had to grind one die in order to do 4/0 cable crimps.
https://www.amazon.com/Hydraulic-Bat...NsaWNrPXRydWU=

Crimper.jpg

[eric@psmnv]

Thanks much, Ampster!

[Mike90250]

This is really such a delicate subject, because you have to know what a proper crimp looks like
this article covers small multi pin connectors, not power cable lugs. https://www.molex.com/tnotes/crimp.html

Here's some more commercial data on crimping

https://www.powerandcables.com/cable-lugs-crimps-hexagonal-v-indent-methods-of-crimping/

https://www.powerandcables.com/crimping-cables-cembre-cable-lugs/

I've just not been able to find any decent sites with pics for you.