Question About Best Practice -- For Electricians

[Dockhead]

One of the things I like about my present boat is the extremely well designed and executed electrical system which, (knocking on wood), has never given me a moment's trouble despite its complexity (lots of systems).

Therefore I avoid molesting it as much as possible, but new electrical gear is installed every year and eventually the system is no longer completely original.

One major change I had no choice but to make was when I installed a Victron charger/inverter which requires all the AC power to be led through it. So what I did was I cut the cable between the transfer switch (shore/generator) on the main panel and the RCD, and pulled two new cables, one power in, one power out, to the inverter in the engine room.

It has worked flawlessly for about 6 years so far.

Last night I installed 3 volt/amp meters to complement my new Smartgauge battery monitor -- one to measure voltage and current coming in from generator or shore power, one to measure voltage and current coming out of the inverter, and one to measure DC system voltage and DC current coming out of (or going into) the charger/inverter.

It's lovely and now I can see at a glance what's going on in my electrical system -- how much power I'm taking out of shore power, how much power is being produced by the inverter, the rate of charge, etc., etc.


HOWEVER, when I made this installation I revisited something I did 6 years ago, and I didn't like it. I used terminal screw blocks to join the main AC power cables, and I didn't like what the ends of the multistranded marine cables looked like. This does not look like best practice to me.

So the first question is -- what's the right way to do this?

I guess I could use heat seal crimp connectors, but I'm afraid the cables are too large for the yellow size ones, and I don't have a crimper for anything bigger. Also, they are not removable, and if -- God forbid -- I ever have another charger/inverter failure, it is really good to be able to jump this connection so that I don't lose all AC power.

I guess I could use small bus bars or junction boxes, but it would be very hard to attach these to anything, in this particular location.


Any ideas or suggestions?



The second thing which bothered me was the power cables to the AC voltmeters. For DC voltmeters I always install a fuse in the positive lead, next to the battery. There is no such provision here, and the cables are exceptionally thin. There is no circuit breaker upstream of these devices other than the breaker on the generator or on the shore power podium -- that makes me a bit nervous. Because of the thinness of the cables, I joined them by phone wrap, solder, several layers of heat shrink, and then strain relief -- I think it's pretty bulletproof, but still -- what if? The cables are so thin that they would burn up in an instant if shorted, and probably couldn't start a fire, but still . . . Is it done to insert a regular fuse into such a lead? Like maybe a 1 amp automotive type?


Thanks in advance for your advice.

[unclemack]

I've usually used bootlace ferrules over wire ends into chocolate blocks if that's what you mean.
Guessing probably not though.

edit: just noticed you said AC, duh, obviously not chocblocks.
Surely you can't mean split-nut domestic fittings?

[unclemack]

These are convenient but you said hard to find space to fit.

Auto Marine Domestic 'M1100' 100amp 2 pole 'service connector' box JUB25 | eBay


These used to be common in UK but don't see them much now. Always liked the one-piece rubber cover for its added safety.
Easy and cheap to make jumper cables ready for bypassing whatever you need.

3 PIN 10 AMP ORANGE RUBBER POWER CABLE LEAD PLUG CONNECTOR REPAIR JOINER | eBay

[Dockhead]

Originally Posted by unclemack

These are convenient but you said hard to find space to fit.

Auto Marine Domestic 'M1100' 100amp 2 pole 'service connector' box JUB25 | eBay


These used to be common in UK but don't see them much now. Always liked the one-piece rubber cover for its added safety.
Easy and cheap to make jumper cables ready for bypassing whatever you need.

3 PIN 10 AMP ORANGE RUBBER POWER CABLE LEAD PLUG CONNECTOR REPAIR JOINER | eBay

Nice looking, but far too small! System can have as much as 29 amps plus 26 amps power boost, short term, 13 amps power boost, continuous, which is 42 amps.

But I get the idea -- will trawl around the net for something like that but higher capacity; thanks!

[Dockhead]

Originally Posted by unclemack

I've usually used bootlace ferrules over wire ends into chocolate blocks if that's what you mean.
Guessing probably not though.

edit: just noticed you said AC, duh, obviously not chocblocks.
Surely you can't mean split-nut domestic fittings?

I mean these:



They are rated for 60 amps and 400 volts, so technically ok, but I don't like the way the wire ends look.

But that's a great idea about bootlace ferrules -- that would be a different ballgame. Maybe a viable option.

[Stu Jackson]

Dockhead, over here we call what you've pictured "Euro strips" and they can handle small wire.

I use larger terminal strips that take ring connectors, like this:

COLE HERSEE Six-Gang Terminal Block | West Marine

[Colin A]

Here in the US we would mostly use large terminal blocks (like from Marathon) with ring terminals. I have seen large Erico terminal blocks used on military boats but the screw terminals bear directly on the strands (which is a no no per ABYC but I think is OK according to CE don't quote me on that thou). For me I would likely take a look at these from Phoenix they should be easy to find at electrical wholesalers in most of the EU.
https://www.phoenixcontact.com/onlin...8-1f90caba3408
https://www.phoenixcontact.com/onlin...7-2d6121721248

[CarstenWL]

... like Colin suggested from Phoenix, Weidmüller, ...

In German they are called 'Reihenklemme' ... Available in different sizes ...

Here is a link to a data sheet for a small, 20-25A / for wires 2.5mm2 flexible or 4mm2 solid one: http://tinyurl.com/hesk4mk

Regards,

Carsten

[smac999]

people still use those euro blocks?... the wire is exposed and the screws just crush wire.


you should have heat shrink ring ends. and screw terminals. the blue sea ones go up to 65a.


https://www.bluesea.com/products/cat...uous_Rating=65


also you'd want to cover it.


you should be able to find AC rated fuses. I would definatlly put something in.

[Dockhead]

Originally Posted by smac999

people still use those euro blocks?... the wire is exposed and the screws just crush wire.


you should have heat shrink ring ends. and screw terminals. the blue sea ones go up to 65a.


https://www.bluesea.com/products/cat...uous_Rating=65


also you'd want to cover it.


you should be able to find AC rated fuses. I would definatlly put something in.

Can't use that without crimping, and I have some doubts whether my crimper can manage that size cable. If it can, then a simple Molex heat shrink butt splice might be the answer.

Sent from my D6633 using Cruisers Sailing Forum mobile app

[Sailorman Ed]

I just changed my incoming AC and used the black terminal blocks like the Blue Sea or Cole Hersee with the yellow ring terminals and jumpers. What I did not like was that the wires were so close to each other. Certainly less than 1/8" spacing, maybe 1/16" (1.5 mm). While they did not arc, if doing again (and I might), I will get a longer block and leave an unused terminal between the hot and white.

BTW, my wind generator uses Anderson disconnects:https://powerwerx.com/anderson-power...-sb-connectors They make these larger enough to accept a 4/0 wire!
I wish they made these as a 3 connector set for AC

[Dockhead]

Originally Posted by Sailorman Ed

I just changed my incoming AC and used the black terminal blocks like the Blue Sea or Cole Hersee with the yellow ring terminals and jumpers. What I did not like was that the wires were so close to each other. Certainly less than 1/8" spacing, maybe 1/16" (1.5 mm). While they did not arc, if doing again (and I might), I will get a longer block and leave an unused terminal between the hot and white.

BTW, my wind generator uses Anderson disconnects:https://powerwerx.com/anderson-power...-sb-connectors They make these larger enough to accept a 4/0 wire!
I wish they made these as a 3 connector set for AC

The Anderson connectors look great! Unfortunately this is for DC and don't seem to be rated for AC.

[Dockhead]

Originally Posted by Dockhead

The Anderson connectors look great! Unfortunately this is for DC and don't seem to be rated for AC.

I take it back, they ARE rated for AC.

This looks like the business!

[unclemack]

Originally Posted by Dockhead

I take it back, they ARE rated for AC.

This looks like the business!

News to me despite having been familiar with Anderson connectors and DC for years.
Just looked at their website and they show SAF-D-GRID 300V AC as "coming soon" - did I miss something?

The only Anderson connectors I've ever seen have contacts that wouldn't be considered safe for mains AC. Too easy to touch the contacts.
Didn't even know they made other types.

[wiekeith]

Originally Posted by Dockhead

One major change I had no choice but to make was when I installed a Victron charger/inverter which requires all the AC power to be led through it. So what I did was I cut the cable between the transfer switch (shore/generator) on the main panel and the RCD, and pulled two new cables, one power in, one power out, to the inverter in the engine room...

-- God forbid -- I ever have another charger/inverter failure, it is really good to be able to jump this connection so that I don't lose all AC power.

I guess I could use small bus bars or junction boxes, but it would be very hard to attach these to anything, in this particular location.


Any ideas or suggestions?

I experienced a melt-down (pics attached) at the mains plug/socket of my Victron 12/1600 charger/inverter, which resulted in exactly what you're trying to avoid - loss of shore-power until it's fixed... And my thinking was the same as yours - how to bypass it if ever it happens again.

As already mentioned by unclemac, inline connectors are a good option, but you'll probably need 20A connectors (my Victron will take up to 16A from shore-power). There are a few suppliers of these, such as those sold by www.tlc-direct.co.uk.

I've not actually modified mine yet as I'll be moving the shore-power inlet at the same time, so there's going to be a bit of glass-work involved, but I will be doing so soon.

Incidentally, the Victron on my boat was about 7 years old when it had the melt-down. The reseller tells me that he's seen it before, so it wasn't a one-off.

I'll let you know how I get on.