On deck electrical connections.

pessimist

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I'm shortly fitting solar panels (3x80 watt) to the new boat. They will be wired in parallel (shading considerations) and the the plan is to have two junction boxes on deck with 2 single wires running down to the controller. I will have a run of 4-5 metres to the controller which I think means 10mm wire. I'm looking for suitable junction boxes and also the connectors to go in them - I know what the experts think of choc blocks, but what's the best alternative. I have ratchet crimpers so bus bars with ring stud terminals would be feasible, but perhaps overkill? The junction boxes will be in a reasonably sheltered position (behind/under a windscreen) so would a box from screwfix be o.k. or is there a better alternative?
Any advice welcome.
Thanks
 

prv

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Anything IP67 or higher should be fine for the box. Doesn't matter where you buy it from.

That said, field-installable IP67 (or higher) connectors of some kind would answer the connection question and also eliminate the need for the box?

Pete
 

northwind

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I'm shortly fitting solar panels (3x80 watt) to the new boat. They will be wired in parallel (shading considerations) and the the plan is to have two junction boxes on deck with 2 single wires running down to the controller. I will have a run of 4-5 metres to the controller which I think means 10mm wire. I'm looking for suitable junction boxes and also the connectors to go in them - I know what the experts think of choc blocks, but what's the best alternative. I have ratchet crimpers so bus bars with ring stud terminals would be feasible, but perhaps overkill? The junction boxes will be in a reasonably sheltered position (behind/under a windscreen) so would a box from screwfix be o.k. or is there a better alternative?
Any advice welcome.
Thanks
Chocblocks are ok, but the main issue is that any stranded wires should be in a bootlace ferrule. 99.9% of people stuff stranded wire in and hope.

If inside a box then Wago connectors are a good alternative. otherwise if you can do away with the junction box then look at solar panel connectors:
Solar Connectors MC3 & MC4
 

lw395

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Cable glands into a sealed box might be a possibility?
One advantage of say bolted ring terminals in a box is that you can access with a voltmeter should you want to.
 

rogerthebodger

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I have 4 solar panels connected in parallel and I have run cables from one terminal block under each panel to the next panel box and so forth. I then take a single 2 core cable down through on leg of my taga to inside the boat then onto the controller.

Doing it this way I don't have any connections at deck level.

If you don't have a taga you can just have a single 3 core cable through a cable gland to take seal the cable at deck level.
 

pessimist

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Thanks everyone. Sadly Wago connectors won't cut it as their max. wire size is 6mm. Lw395 describes pretty much what I had in mind and I like Rogershaw's idea but wonder if I can effectively seal the terminal block with two wires on each gland rather than one.
Food for thought.
 

PaulRainbow

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I'm shortly fitting solar panels (3x80 watt) to the new boat. They will be wired in parallel (shading considerations) and the the plan is to have two junction boxes on deck with 2 single wires running down to the controller. I will have a run of 4-5 metres to the controller which I think means 10mm wire. I'm looking for suitable junction boxes and also the connectors to go in them - I know what the experts think of choc blocks, but what's the best alternative. I have ratchet crimpers so bus bars with ring stud terminals would be feasible, but perhaps overkill? The junction boxes will be in a reasonably sheltered position (behind/under a windscreen) so would a box from screwfix be o.k. or is there a better alternative?
Any advice welcome.
Thanks

10mm cable from the panels to the controller seems a bit over the top.

How about fitting each panel with a two wire gland, then making all connections below deck, in the dry and out of sight ?

These look very neat in use: 12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine
 

davidmh

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I suspect by 10mm cables the OP means a 10mm OD cable which is probably 2 x 2.5mm sq wire with outer covers this is the normal cable for Solar. if the system is big or very long you can get 4mm sq wires.
 

Solent sailer

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Use a decent plastic box and pvc stuffing glands, wago connectors are great and save you having to get boot lace ferrels, then fill the box with "magic gel".
I use it at work and its great when a gland or box might leak, it's easy to remove if necessary if a bit messy.
 

pessimist

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10mm cable from the panels to the controller seems a bit over the top.
ca
How about fitting each panel with a two wire gland, then making all connections below deck, in the dry and out of sight ?

These look very neat in use: 12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine
Oh b@gger (goodness me, what a nuisance) I could have saved a bob or two on the cable. I used this calculator which recommended 6mm for 3% loss or 10mm for 2%. I played safe:(. Like the glands though.
 

PaulRainbow

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Oh b@gger (goodness me, what a nuisance) I could have saved a bob or two on the cable. I used this calculator which recommended 6mm for 3% loss or 10mm for 2%. I played safe:(. Like the glands though.

If you use the glands to get into the boat you can then either run 3 x 2.t twin flex cables to the controller. Or run the cables that are fitted to the panels as far as they will go, then use 4mm cable for the rest, which will allow the use of Wago connectors.

Remember, when using the calculator that the voltage will be 18-20v, not 12v and if you calculate for individual panels, 2.5mm is very low voltage drop.
 

PetiteFleur

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I used Index marine pear shaped deck glands for a pair of cables. better than the usual glands as the cables lie parallel to the deck. Supplied with various sizes or they do single glands which will take larger cable. From memory they are 2.5mm cable fitted to the solar panels. I made connections inside the boat using Wago connectors See Index Marine SE7B Black Cable Gland for the dual glands, available in black and white but the black are cheaper.
 

thinwater

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Chocblocks are ok, but the main issue is that any stranded wires should be in a bootlace ferrule. 99.9% of people stuff stranded wire in and hope....

This depends a great deal on whether the choc block includes a pressure plate for the wire. With a good pressure plate they are fine, without, not so much.

There may also be a wire size limitation, relegating you to standard terminal blocks.
 

Stemar

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This depends a great deal on whether the choc block includes a pressure plate for the wire. With a good pressure plate they are fine, without, not so much.

There may also be a wire size limitation, relegating you to standard terminal blocks.
The other thing that gets choc blocks their bad rep is that all choc blocks are not equal. I've got a load in my workshop where the screws are "magnetic brass". They aren't allowed anywhere near the boat. They were a fraction of the price of the ones in the chandlers, but for good reason. For once, "marine quality, Sir" actually means something.
 

rogerthebodger

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The other thing that gets choc blocks their bad rep is that all choc blocks are not equal. I've got a load in my workshop where the screws are "magnetic brass". They aren't allowed anywhere near the boat. They were a fraction of the price of the ones in the chandlers, but for good reason. For once, "marine quality, Sir" actually means something.

choc block with a pressure plate and stranded wire can give a larger wire/connector contact area where a crimp terminal cn create a point contact
 

PaulRainbow

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choc block with a pressure plate and stranded wire can give a larger wire/connector contact area where a crimp terminal cn create a point contact

I have to agree with you again Roger. IMO, if using anything with the "pressure" plate, don't use ferrules. You'd never use a ferrule with a lever lock Wago, for instance. Without the plate, a ferrule is pretty much a must.
 
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