MC4 Connectors for 8 AWG Wire Connecting to MC4 for 10 AWG Wire

[Santa]

Hi Everybody,

I am finally continuing to finish my set up and I am following (almost) Will's blueprint here: https://www.mobile-solarpower.com/simplified-400-watt-fewer-wires-and-alternator-charging.html BUT, I will be using 8 AWG wires coming from the SCC to the Y-branch connector. So here are my questions to anyone who can help:

1. Can anyone tell me where to get MC4 connectors that accommodate 8 AWG (10 mm I believe)?

2. Does anyone know of a cheaper MC4 crimper tool that does 8 AWG that's not over $300? That's all I could find. (looking for cheap).

3. The Y-branch connector that Will has in the link (at the above blueprint) is 10 AWG, I believe. I want to know if the MC4 connectors are the same when it comes to connecting them to the 8 AWG MC4 connectors. In other words, will they fit together? Is it only the part where the wire goes in that is the difference?

4. Also, will it be a problem using the 10 AWG Y-branch connectors with the 8 AWG wire? In other words, will I need to find a y-branch connector that is 8 AWG?

I hope I explained that correctly. If not, please ask me to clarify.

Hoping everyone is doing well...

 

[Santa]

 

[JoeHam]

I bought this one :

IWISS Solar PV Panel Crimping Tool Kit with Wire Cutter Spanner and Connectors - Crimpers - Amazon.com

IWISS Solar PV Panel Crimping Tool Kit with Wire Cutter Spanner and Connectors - Crimpers - Amazon.com

www.amazon.com

Under $300 by a little bit. ?

Wire size not specified so ask there or there are others with wire size specified.

 

[Santa]

I bought this one :

IWISS Solar PV Panel Crimping Tool Kit with Wire Cutter Spanner and Connectors - Crimpers - Amazon.com

IWISS Solar PV Panel Crimping Tool Kit with Wire Cutter Spanner and Connectors - Crimpers - Amazon.com

www.amazon.com

Under $300 by a little bit. ?

Wire size not specified so ask there or there are others with wire size specified.

Yeah, that is for the smaller diameter of wire. Thanks any way...

 

[JoeHam]

I think it would work but more than likely this is the issue:

Does a MC4 or Amphenol connector work with 8 AWG size wire?

With industry-leading service and equipment, Greentech Renewables helps solar contractors install top quality solar PV systems, gain competitive advantage and grow their business.

www.cedgreentech.com

 

[Santa]

I think it would work but more than likely this is the issue:

Does a MC4 or Amphenol connector work with 8 AWG size wire?

With industry-leading service and equipment, Greentech Renewables helps solar contractors install top quality solar PV systems, gain competitive advantage and grow their business.

www.cedgreentech.com

Thanks for that info. My SCC came with 8 gauge lugs/connectors and an expert here recommended 8 gauge wire for my set up...hmmmm.....

 

[Santa]

BTW, there are MC4 connectors that work with 8 AWG, I just can't find them now...

 

[Bob142]

BTW, there are MC4 connectors that work with 8 AWG, I just can't find them now...

Welcome back, Santa.

They definitely exist. WindyNation sells ready made cables. Maybe an option for you?:

8 AWG 8 Gauge Pair Black + Red Solar Panel Cable Wire with Solar Connectors | eBay

One Pair (1 piece black cable + 1 piece red cable) of UL Listed 8 AWG Solar Extension Cable with Solar Connectors. 8 AWG Solar Cable Technical Specifications Wire Thickness: 8 AWG. Made in the USA solar cable.

www.ebay.com

And I found these 8 AWG MC4 connectors on eBay:

10 pairs PV Connector compatible with MC4 for 8AWG wire, 1500v, Male/Female | eBay

Connector is UR listed.

www.ebay.com

What I can't find is a crimp tool for that size under the $300 range...

 

[Santa]

Welcome back, Santa.

They definitely exist. WindyNation sells ready made cables. Maybe an option for you?:

8 AWG 8 Gauge Pair Black + Red Solar Panel Cable Wire with Solar Connectors | eBay

One Pair (1 piece black cable + 1 piece red cable) of UL Listed 8 AWG Solar Extension Cable with Solar Connectors. 8 AWG Solar Cable Technical Specifications Wire Thickness: 8 AWG. Made in the USA solar cable.

www.ebay.com

And I found these 8 AWG MC4 connectors on eBay:

10 pairs PV Connector compatible with MC4 for 8AWG wire, 1500v, Male/Female | eBay

Connector is UR listed.

www.ebay.com

What I can't find is a crimp tool for that size under the $300 range...

Wow! Thanks Bob! I've been on Ebay, but I couldn't find them so THANKS! I don't need 10 pairs, but...it may be my only option, so that's okay. Thank you again!!!

 

[Santa]

P.S. I already have the wire for my set up

 

[OHIO_Tom]

Welcome back, Santa.

They definitely exist. WindyNation sells ready made cables. Maybe an option for you?:

8 AWG 8 Gauge Pair Black + Red Solar Panel Cable Wire with Solar Connectors | eBay

One Pair (1 piece black cable + 1 piece red cable) of UL Listed 8 AWG Solar Extension Cable with Solar Connectors. 8 AWG Solar Cable Technical Specifications Wire Thickness: 8 AWG. Made in the USA solar cable.

www.ebay.com

And I found these 8 AWG MC4 connectors on eBay:

10 pairs PV Connector compatible with MC4 for 8AWG wire, 1500v, Male/Female | eBay

Connector is UR listed.

www.ebay.com

What I can't find is a crimp tool for that size under the $300 range...

Try looking at this
Goplus 16 Ton Hydraulic Wire Crimper Battery Cable Lug Terminal Crimping Tool on Amazon

 

[Santa]

Try looking at this
Goplus 16 Ton Hydraulic Wire Crimper Battery Cable Lug Terminal Crimping Tool on Amazon

I believe that is for lugs. I need an MC4 crimper.

 

[iceledoar]

Wow! Thanks Bob! I've been on Ebay, but I couldn't find them so THANKS! I don't need 10 pairs, but...it may be my only option, so that's okay. Thank you again!!!

I ended up ordering cables with ends on from windy nation and bypassed the tool. As for combining, I am not sure I would use y connectors, I’m considering building a combiner box and using QO breakers for each string. That way I can use a small 220 exterior rated breaker box and the neutral bus becomes the negative for the panels. No crimp connections, accommodates 8 agw and improves safety.

 

[Hedges]

I’m considering building a combiner box and using QO breakers for each string. That way I can use a small 220 exterior rated breaker box and the neutral bus becomes the negative for the panels.

What Voc are your strings of PV panels?

Your comment makes it sound like you plan to use single-ended QO breakers referenced to neutral and think they would work up to 220VDC. They are OK up to 48VDC (and I'm guessing up to 62.5VDC athough that violates the listing.) But not up to 220V!

Following links from other threads I found a mention of 48V rating for QO (peak voltage, meaning not good enough for 48V nominal battery.) So I searched the topic and found these:

Are QO load centers suitable for use on a 125V DC application? | Schneider Electric USA

https://download.schneider-electric.com/files?p_enDocType=Data+Bulletin&p_File_Name=0601DB0401.pdf&p_Doc_Ref=0601DB0401

Those say the QO breakers are UL listed for 48VDC, but the panels and 2-pole breakers used for + and - are "Square D Certified" for 125VDC (whatever that means!) I figure if 2 poles works for 125VDC then each pole handles 62.5VDC.

The interrupt current ratings are 4k, 5k, 10k amps. Certainly good enough for PV strings, but only small battery banks not large ones.

 

[iceledoar]

So the 220v rating I’m referring to is for the breaker box. This would normally be used for ac but QO breakers can be used for dc applications, such as PV strings. Bring the series string/s into the box and run the positive lead through the breaker. I currently have only one string @48vdc max, and don’t have a need to combine in parallel with another string.

 

[iceledoar]

What Voc are your strings of PV panels?

Your comment makes it sound like you plan to use single-ended QO breakers referenced to neutral and think they would work up to 220VDC. They are OK up to 48VDC (and I'm guessing up to 62.5VDC athough that violates the listing.) But not up to 220V!

Following links from other threads I found a mention of 48V rating for QO (peak voltage, meaning not good enough for 48V nominal battery.) So I searched the topic and found these:

Are QO load centers suitable for use on a 125V DC application? | Schneider Electric USA

https://download.schneider-electric.com/files?p_enDocType=Data+Bulletin&p_File_Name=0601DB0401.pdf&p_Doc_Ref=0601DB0401

Those say the QO breakers are UL listed for 48VDC, but the panels and 2-pole breakers used for + and - are "Square D Certified" for 125VDC (whatever that means!) I figure if 2 poles works for 125VDC then each pole handles 62.5VDC.

The interrupt current ratings are 4k, 5k, 10k amps. Certainly good enough for PV strings, but only small battery banks not large ones.

These type breakers would go between the POV strings and the SCC. Not on the battery. Jus as a combiner.

 

[Santa]

I think this thread from the OP (me) has gone way off and isn't answering my questions. All I really need is #2 question answered from OP. Thanks

 

[Hedges]

I believe that is for lugs. I need an MC4 crimper.

I have the Harbor Freight version of that hydraulic crimper ($60) and was able to crimp 10 AWG MC4 lugs with one of the die sizes.

Hydraulic Wire Crimping Tool

Amazing deals on this Hydraulic Wire Crimping Tool at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

Because it has hex die, it only shrinks the connector slightly in terms of cross-sectional area. The wire needs to be a close fit before crimping, unlike those general purpose crimp terminals that fit a wide range of wire gauges using a different type of tool.

Someone who really knows crimps (and does battery cables for several hundred amps and marine applications) tried out this crimper and had bad things to say about it, but for me it's an upgrade to a cheap plier-style crimper. I wanted a commercial grade crimper for large lugs (e.g. Thomas-Betts) but didn't want to spend over a grand.

TBM8S Compression Crimper with Dies

Tool Kits, Tool Cases, Datacom Tools, Telecom Tools.. All for sale online at Tecra Tools

tecratools.com

 

[Santa]

I have the Harbor Freight version of that hydraulic crimper ($60) and was able to crimp 10 AWG MC4 lugs with one of the die sizes.

Hydraulic Wire Crimping Tool

Amazing deals on this Hydraulic Wire Crimping Tool at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

Because it has hex die, it only shrinks the connector slightly in terms of cross-sectional area. The wire needs to be a close fit before crimping, unlike those general purpose crimp terminals that fit a wide range of wire gauges using a different type of tool.

Someone who really knows crimps (and does battery cables for several hundred amps and marine applications) tried out this crimper and had bad things to say about it, but for me it's an upgrade to a cheap plier-style crimper. I wanted a commercial grade crimper for large lugs (e.g. Thomas-Betts) but didn't want to spend over a grand.

TBM8S Compression Crimper with Dies

Tool Kits, Tool Cases, Datacom Tools, Telecom Tools.. All for sale online at Tecra Tools

tecratools.com

I need it for 8AWG MC4's

 

[Hedges]

I need it for 8AWG MC4's

Kit includes hex die labeled 0, 2, 4, 6, 7, 8, 10, 12, 14 AWG.
But really terminal size (including wall thickness) is what the die has to fit.
Perhaps one will do the job for you. HF has a return policy, and if there's a store local to you, you could open the package and see how a connector fits.

https://shop.harborfreight.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/6/6/66150_W3.jpg