Hello, first time posting here. I’m looking for help with installing a Multiplus 2 in a marine application. My boat is 30amp and wired with 10AWG AC wiring. I need to connect this into and out of the Multiplus but I can’t find detailed information on the acceptable gauge range for the Phoenix Contact input and output connectors as to the minimum gauge they accept. I’m wondering if I should splice in 6AWG and us that, or somehow use a large ferrule on the 10AWG. It would be helpful if the manual gave some more information on this. BTW, I have a 30 amp breaker on the supply line so that line is protected, but as of now no breaker on the output of the multiplus.
Any ideas on best practices would be greatly appreciated!
Welcome Laurence,
10 AWG is 30 amp cable. No reason to upgrade unless you are running long distances. Just make sure all your connections are very good. Bad or loose connections are a common failure point especially in the multiplus 2. They have those lame push in connectors on the terminals. I wish they would just make them screw terminals and be done with it. If you are using solid copper you will have a little easier time pushing it into the terminal since it doesn’t flex as much as stranded. I use SOOW stranded wire with ferrules because I like the protection and flexibility of the SOOW cable. Then I use my terminal tool(modified small flat head screwdriver) to hold the terminal open while I insert the wires. Then double and triple check for good connection. I recently serviced a rig with a Multiplus 2 that melted the terminals at a poorly seated connection. The original installer is replacing the entire unit since the terminal block is melted. Similarly I have found melted connections at loose wire nut connections in junction boxes and transfer switches.
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Hi @lwarden, welcome to our community.
Supply-side protection is one thing, but keep in mind that the MultiPlus II can add extra current as PowerAssist, on top of the current available from the supply. I don’t know which Multi you have, but depending on the model it can easily be 30 A or more. That’s why, even if 10 AWG is sufficient on the supply side, downstream of the MultiPlus you may indeed need to upgrade the wiring
As for the wiring, it depends on the power rating and nominal voltage of the Multi, and you didn’t mention which model you chose. For the basic 3000VA / 120V models, the specs list 6 AWG as the connection terminal size. The same applies to the 3000VA / 230V version.
From my own experience, 10 mm² wires with ferrules fit without any problem. I don’t have hands-on experience with 6 AWG wires. That said, Victron generally does not recommend using ferrules, and prefers the wires to be connected directly.
Thanks @tstiller and @TherealKT for the feedback. I’m installing a 3000VA / 120V model. I have the output leading directly to a 30A breaker before the loads, so in a sense it’s protected from drawing more than 30A from the multiplus if it uses PowerAssist. This breaker is located about 15’ away and connected via the 10 AWG conductors so if there were a short somewhere I suppose it could cause an issue, but seems unlikely.
It seems this input/output spring terminal is not a great design by Victron, I would much prefer to have screw terminals. I have a background designing instruments for several markets, I personally wouldn’t design these into any product.
There is a thread going around on spring terminals for power wires. Have you seen it?People disagree on the suitability of these. Apparently, the European versions have screw terminals. I have a Quattro with screw terminals and I’m not complaining. Americans have a (unfair?) reputation of liking “simple” things like automatic cars and breakers.
Yeah, we Americans are due for taking some jabs. I’ve seen the posts on the spring terminals. The issue I have is the Multiplus is located horizontally under a seat, so access is difficult to get the wires in these terminals. If they were screw terminals I would be done already, but as of now I’m messing around trying to figure out the best way to do it. And worse is there is no recommended minimum wire size for the terminals, and I can’t find the actual part on the Phoenix Contact website to see what they have to say. I’m now considering double backing the wire and fitting an appropriate ferrule which should give a little less than the area of a 6 AWG wire. If it were easier to get to I could also flow some solder down the ferrule, but that isn’t happening.
You are illustrating exactly what the problem is. The Multiplus II is often installed in places where it is difficult to get at. When I install one I try to install the cables before I actually mount it to insure the cables are seated securely. This is not always the ideal way to install a MP in every scenario. Sometimes I really wish I could mount the MP first, get it where I want it and then route my cables. My biggest beef with the push connectors is servicing them after installation when the unit is already mounted, as you said, under a seat in a pass through compartment or other common places on RVs. The recent issue I had on a service call had just this problem. And this wasn’t the first time. The installer didn’t get the very inflexible 10 AWG romex pushed all the way into the terminal and it melted. I could barely get my terminal release tool(modified screwdriver) into the slot to release the terminals and it was doubly challenging to get the wires back in. In the end the melted terminal ended up breaking. The installer is replacing it with a new MP. This is not the first time I have service a multiplus with this problem.
SO all this whining is not for nothing but to make the point that all this heart ache, or better said pain in the a**, could have been avoided with a simple screw in terminal. Call me a typical American but I think the push terminals on the multiplus absolutely suck. There, I feel better.
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Well, the drama continues today. After a very frustrating couple hours I managed to get the AC lines with proper, long ferrules crimped on into the terminal blocks. However, on the line in, the hot and neutral terminals seem compromised. I don’t know if it was all the fussing in and out with the wire and the screwdriver, but the neutral line does not hold the wire in place if you pull, and I had a very difficult time getting the hot in as well. So infuriating. I literally have spent 4 hours trying to get this connected. Now I feel the terminal block has internal damage on the line in.
After some digging around, I believe these are Phoenix Contact P/N 1735794 or something really similar. They are available from Mouser and Digikey.
https://www.mouser.com/ProductDetail/Phoenix-Contact/1735794?qs=JbOBE5X8Ds90166H5kff9A%3D%3D
The spec sheet includes much more detail about the rated wire gauges and includes the use of ferrules. I see there is a lot of conflicting information from Victron about ferrules, but it’s clear that PC includes them in the spec.
At this point I’m really disappointed at where this project has gone. I was so excited about installing all these components, and had heard such great things about Victron, but now this has left a bad taste in my mouth and to be honest, I’m not sure how to proceed. I will call the distributor, but now that I have it installed I’m in a tough spot. I’ll probably order a couple of the terminals just in case I need to swap them out.
You guys don’t know me from Adam, but I’m not a noob when it comes to working with electrical equipment and marine wiring, but I feel really lame and am kicking myself at the moment.
Here is a cross section of the part in case anyone is interested in the guts of it.
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Lawrence, just so we’re on the same page: you installed the device in a spot with very limited service access. Then, while trying to wire it under those conditions, you apparently managed to damage the connection terminal with a screwdriver.
And based on this, you’ve concluded that the manufacturer is at fault?
Spring terminals are a well-established industrial standard used worldwide, and Phoenix Contact isn’t exactly an unknown brand in this space. These terminals work just fine when they’re not being abused.
That said, I’ll admit that I personally also prefer traditional screw terminals — when I have a choice. Still, when I do have to use spring terminals, I have no issues with them as long as they’re treated with a bit of respect.
The key point here is how you open this type of connector. If you use a screwdriver that’s too large, you’ll simply over-bend the internal spring, and once that happens, there’s no going back.
If something isn’t working here, the explanation is far more likely related to the installation than to any mysterious design flaw.
I’m done listening to people try to explain all the nuances and special ways these terminals need to be treated to get them to work correctly. The simple answer is they are not easy to use, the difficulty of use makes them a liability and are not the best terminal for this application. Victron is no doubt the industry leader in this category of inverter and needs to come up with a terminal that matches their reputation.
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I’ve got an even simpler explanation: maybe you just don’t know how to use them. Instead of complaining about the manufacturer, maybe try learning how the gear actually works?
Victron is very DIY-friendly as a company, but they also repeatedly point out that installing this equipment requires specialist knowledge and often specialist tools. If that’s beyond your comfort zone, the radical idea would be to let someone who does this for a living handle it.
And before this turns into yet another “my solution is better than yours” debate: in my professional career I’ve seen dozens of installations fail electrically for one very boring reason — screw terminals that were never serviced or re-tightened. Spring terminals don’t suffer from that problem. That’s not an opinion, that’s just reality.
Any idea how difficult it would be to remove and re solder new terminals? I am not proficient at something like that but curious.
If someone has experience repairing electronics, this is actually quite straightforward — but it really depends on what tools Laurence has on hand and how comfortable he is with a soldering iron. Laurence will definitely need a soldering iron with sufficient power, plus some form of desoldering tool. Even the most basic spring-loaded syringe-style pump will do.
Of course, the entire Multi will have to be completely disassembled, which only requires basic tools. Everything is held together with standard screws — there are no hidden clips or anything like that. I strongly recommend taking photos during disassembly so you know how to put everything back together afterward.
I probably don’t need to point out that even attempting this will void the device warranty. If I were in Laurence’s position, I’d contact the seller and ask how much a replacement power-terminal board costs — that way, there’s a chance the warranty can still be preserved.
Appreciate the comments and perspective. @tstiller I expect Victron to provide a replacement unit under warrantee. I followed the poorly written directions for AC wiring, used a 2.5mm screwdriver to help open the terminal for the wire. I even looked up and watched several videos to help understand how to do the wiring and still had a failure. Perhaps the spring in the one which does not hold the wire wasn’t tempered properly?
For the record, and this is from 40 years of developing medical and scientific instruments, this is a poorly selected component for use in less than ideal physical access environments. I have specified and use Phoenix Contact terminals many times in the products I design, I’m very familiar with them and I do consider them to be good quality. However, I only use the spring version on smaller communication lines, and we always use a ferrule on the stranded wire. For anything over 14 AWG we would use a screw terminal version of their products. Take that as you will.
I think the issue is that with a ferrule on the end, if it’s not dead center when you insert it a sharp edge can catch the side of the internals of the spring clip, and when you put some force in it, bad things happen. It could also be that repeated screwdriver insertions can weaken the spring, and that may be the issue I have. However, I see very little information in the manual about the care and feeding of these terminals. If it’s so fussy about insertion of the tool, they should provide one which has a stop on it to prevent overstressing the spring clip.
Lastly, I have access to a full electrical engineering shop with all the necessary de-soldering equipment and would not hesitate to replace one of these, or have one of my technicians do it. I hope it doesn’t come to that and that Victron will take care of it.
Bottom line, Victron needs to improve the documentation on the AC side for the Multiplus II manual. They should include the information I posted above from Phoenix Contact on the use of ferrules and long-term and specify a maximum force you should exert on the wire during insertion. Also, they should seriously consider changing these to either screw-down or better yet, ring terminals for the AC line.
Hello, can you please tell me what size ferrules you used to connect your 10awg soow leads in and out of the multiplus ii 12v/3000? I’m
Having a hard time figuring this out . Thank you !
No problem. I use the same ferrules for 6 and 10 gauge. I had to search for a while to find some without the insulator on them and that were longer. You can always cut off the insulation if you need to also.
I just make sure they are thoroughly crimped on. The last thing you want is to have the wires pulling out of the ferrule. I have a pretty decent 6 sided crimper too. I usually do multiple crimps on each ferrule and then pull on it like the dickens to make sure it is secure.
Thanks very much! Where did you buy these ferrules ?
Thanks very much!