8AWG to 10AWG wire for solar

[Travelmonkey]

My RV was pre-wired (using a Zamp 3 port thing on the roof).  The cables to the solar controller look like 6 or 8 gauge.  My solar controller can fit max 10 gauge.  Are there adapters?  What do you guys recommend?

 

[doublegregg]

i'm interested in replies to this....... i just got my first controller, and one of the main reasons i got it (epever) was its inputs, which can take up to 4 gauge,,,, i think... however, drawback is customer support is in china......... i think renogy et al had pretty small inputs. all i can figure is right where you terminate at the controller, you gotta splice in a smaller gauge. is that what you're thinking?????

 

[Travelmonkey]

I was thinking of using something like this: https://www.amazon.com/12-10-Step-Down-Heat-Shrink-Splice-Terminals/dp/B00NVCNQC8

I have no experience with them so I am hoping someone can provide guidance.

 

[doublegregg]

i haven't heard of those (a step down or up), but it looks like it would work.... connectors are pretty complicated.....at least to me. there are so many...

 

[bullfrog]

I hate connections if I can avoid them I do. My new camper was prewired but required a special plug and used a smaller wire. Since my batteries are mounted on the tongue and I have a storage compartment directly behind the battery box I just ran the larger wire with no connectors and used the existing hole. If you are going from an existing larger stranded wire to smaller I usually cut out a few strands and solder the remaining strands together to form a good connecting surface. I’m sure there are several other ways to do this but this is my way if the existing wire is larger and long enough and won’t fit in the clamp terminal.

 

[MikeRuth]

What Bullfrog said!!! Just trim the end of your wire enough to fit the connector, you don't even need to solder it.

 

[highdesertranger]

or use a terminal strip/buss bar. highdesertranger

 

[maki2]

you can't always tell what gauge a wire is just by looking at the outside protective coating. Some versions of wiring such as a wire that would be made to withstand weather has an extra thick protective coating on it. There are metal wire diameter gauges around. Or you can use a chart like this one that states what the diameter of the bare wire is for what gauge. https://powerwerx.com/help/wire-gauge-awg-reference-table

To figure out the diameter calipers are useful. But what if you don't have a calipers? Well maybe you have a set of drill bits around with known fractions. You could then do a side by side comparison of them, what looks to be the closest drill and them convert the drills fractional size into decimals. Of course there are also charts online that convert drill fractions into decimals. Then use that number along with the wire gauge chart and possibly figure out what is the closest match of wire gauge.

Or of course you could just open the Zamp website and write to them asking what size wire gauge they are using. Unfortunately they do not state it on the website and it is not in their FAQ questions and answers.

I love having a digital caliper. What a great invention, easy to read and nowadays they are not very expensive. Unless you are a machinist or engineer or mechanic who need very precise measurements you don't need a high end, expensive one. The inexpensive ones from Harbor Freight or you local hardware store will work just fine for everyday use figuring out hole sizes, inside and outside diameters of objects, the length of a bolt or screw, the dept of an hole, how thick is an object, etc.

 

[maki2]

To answer your question about adapters. You can find them online using the keywords "step down butt splice" . They have a different wire gauge at each end.

I will be using a couple of them this week when wiring up my trailer brakes as the gauges of wire I need to connect together are not close enough for a regular butt splice connector. As it is outside on my trailer tongue I also need a heat shrink adhesive splice topped with a length of heat shrink tubing. Fortunately I can purchase those heat shrink step down butt splices at my neighborhood marine supply store.

 

[Travelmonkey]

Lots of good info here. Thank you all for the replies and suggestions. I’ll post an update when I complete my project. I think I will use the step down butt connectors. I think I will still need to trim one end as it seems to be more difficult to find butt connectors that are wider than 10AWG.

Maki2 - I do have digital calipers from my reloading kit. I would have never thought use them. Good tip.

 

[maki2]

i haven't heard of those (a step down or up), but it looks like it would work.... connectors are pretty complicated.....at least to me. there are so many...

I  buy them as waterproof heat shrinks connectors at my local marine supply store

 

[maki2]

Lots of good info here.  Thank you all for the replies and suggestions.  I’ll post an update when I complete my project.  I think I will use the step down butt connectors.  I think I will still need to trim one end as it seems to be more difficult to find butt connectors that are wider than 10AWG.

Maki2 - I do have digital calipers from my reloading kit.  I would have never thought use them.  Good tip.

West Marine carries 8AWG butt connectors with a nylon coating. But as my crimp tool only goes up to 10AWG for coated connectors I have to strip the coating off then they will fit into the 10AWG space on my crimp tools. I then need to use heat shrink tubing to protect them.

In the marine business there is a need for the stores to stock at least a few of the 8AWG connectors as well as larger connectors for the terminals used for the  wires used for 12v battery terminals. So if you have a marine supply store around call them and ask if they have what you need in stock. Marine is different than automotive, more variety of wire gauges are used.

You should also be able to find them at the electrical supply stores that are used by the electrical contractors. It won't be hard to find in a city of size. But likely not every small town. Fortunately for me there are quite a few marine supply stores just a short distance away as well as an electrical contractor store. I also have pretty good luck finding things at my local Do-It-Best Hardware chain store but they are more limited than the marine supply stores.