diy solar

diy solar

What cable do I need????

feverdog

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Oct 1, 2021
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Newbie here.

I bought a Delta Pro Max and I'm trying to get wired for it. I bought 3, 200 watt rigid panels from Rich solar and some cable to run it in the house. I bought my first 10 ga spool. The wire was about half the diameter of the wire on the panels and too small to make a tight seal on the MC4 connectors.
Bought another spool..........same problem. I thought MC4 uses 10 ga wire. What is the problem?
 

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An MC4 connector should seal with a little compression sleeve that gets pressed in once you tighten the connector:

parts-of-a-connector-mc4-male-and-parts-of-a-connector-mc4-female-min-scaled.jpg


Should just work? And yes, 10 gauge (6mm²) is common.
 
Works with 10 awg and smaller without issues ( I tested with landscape low voltage wiring maybe 18 awg), just be aware and install as above diagram. Also once the pin (Female connecting plane, Male connecting plate) in above drawing is installed. It is not reversible and they are designed not to be removed or reused once installed. I put my first connector strain reliever and compression sleeve on incorrectly and could not get the pin out to correct, other than to cut of connector and start again. I did look at pin removal procedures, but no luck.
 
An MC4 connector should seal with a little compression sleeve that gets pressed in once you tighten the connector:

parts-of-a-connector-mc4-male-and-parts-of-a-connector-mc4-female-min-scaled.jpg


Should just work? And yes, 10 gauge (6mm²) is common.
The problem with the MC4 connector, as I've only recently started using them, is that (seemingly) 25% of the sources of info show that top connector as the "male" connector, while the other 75% show it as a "female" connector. Or it can be 50/50 depending on where you're looking at. So I've stopped calling them either one. The key is just to remember how they go together and which one is + coming from the panel. I think the root of the problem is that some are seeing the protrusion on the top connector as the defining part that make it "male", while others are using the socket of the electrical connection point to indicate the "female".
 
The problem with the MC4 connector, as I've only recently started using them, is that (seemingly) 25% of the sources of info show that top connector as the "male" connector, while the other 75% show it as a "female" connector.

Yes, that's because whoever designed it is an idiot. From the Wikipedia article:

"The MC4 system consists of a plug and socket design. The plugs and sockets are inside plastic shells that appear to be the opposite gender - the plug is inside a cylindrical shell that looks like a female connector but is referred to as male, and the socket is inside a square probe that looks male but is electrically female. The female connector has two plastic fingers that have to be pressed toward the central probe slightly to insert into holes in the front of the male connector. When the two are pushed together, the fingers slide down the holes until they reach a notch in the side of the male connector, where they pop outward to lock the two together."

Who does that...

Anyway, yes, the image I used is technically wrong, but I only used it to illustrate the 'compression sleeve'. Also, OP doesn't seem to use double insulated cable, which is also likely the cause of the issue he's facing.
 
Yes, that's because whoever designed it is an idiot. From the Wikipedia article:

"The MC4 system consists of a plug and socket design. The plugs and sockets are inside plastic shells that appear to be the opposite gender - the plug is inside a cylindrical shell that looks like a female connector but is referred to as male, and the socket is inside a square probe that looks male but is electrically female. The female connector has two plastic fingers that have to be pressed toward the central probe slightly to insert into holes in the front of the male connector. When the two are pushed together, the fingers slide down the holes until they reach a notch in the side of the male connector, where they pop outward to lock the two together."

Who does that...

Anyway, yes, the image I used is technically wrong, but I only used it to illustrate the 'compression sleeve'.
I try not to use the word "idiot" very often. But in this case, I'm pretty much ok with you using it. ;)

I built up a few cables last night and this connector is growing on me. I like the design of that compression sleeve, so far. I especially like the potential it has for supporting different diameters of wire. But I'll probably with 10 gauge that I bought a roll of.
 
The problem with the MC4 connector, as I've only recently started using them, is that (seemingly) 25% of the sources of info show that top connector as the "male" connector, while the other 75% show it as a "female" connector. Or it can be 50/50 depending on where you're looking at. So I've stopped calling them either one. The key is just to remember how they go together and which one is + coming from the panel. I think the root of the problem is that some are seeing the protrusion on the top connector as the defining part that make it "male", while others are using the socket of the electrical connection point to indicate the "female".
Thanks for pointing that out. In all the vehicle connectors etc that I have dealt with, the male/female designation is always determined by the actual pin and socket, not the plastic housing.
 
don’t get me started about disconnecting MC4 connectors! this one CIGS panel came with one that has a PLASTIC SHIELD?! which necessitates a tool to unlatch the mechanism.. what!!!!!? it’s designed for up to 600VDC system but come on!!!

normal ones have a mechanism that encourages the hands to fly apart when it finally unlatches, maybe this is part of the infinitely wise “safety”

1633643806406.jpeg

if your hands are flying apart because of the abrupt unlatch mechanism, the DC arc will self extinguish quickly ?
 
And instead of just using a twist action to connect and disconnect, you need some dinky piece of plastic to disconnect it...
The first few times I actually used these connectors, I used my finger tips to push in the retainer clips. It took a little work, but was do-able. But it hurts old fingers. I kept thinking, there's got to be a better way and I don't want to carry large needle nose pliers around. Just got my crimper kit a few days ago and was very happy to find the little plastic wrenches with the prongs for this. Very handy. But yes, still a "dinky piece of plastic" that you still need.

Edit. Oh, I see there are versions with covers over the outter side of the retainer clips. The fingers are not going to work on those at all. Back to the needle nose or the dinky little plastic tool.
 
I think it realistically should be able to handle that voltage. It would not take too many 72 or 96 cell panels in series to reach that voltage.
Point well taken; my confusion is with the retention mechanism. I kind of assumed that high system voltage and DC arc hazard dictated the use of this dastardly outer shield which prevents using hand to unlatch.
1633643887907.png
The only motivation I could think of to include this cursed outer wall is to ensure a tool is used for disconnecting them. It vexes me so.
 
I kind of assumed that high system voltage and DC arc hazard dictated the use of this dastardly outer shield which prevents using hand to unlatch.
The risk is still there regardless of what tool is used. They should never be disconnected under load and the latching mechanism does not prevent that. I just like the fact that once you hear the click you know they are waterproof and secure. In my mind they are a big improvement over the older MC3 connectors.
 
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