Multiplus-II Case Ground - Corrected
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- Опубліковано 23 сер 2024
- Previously we connected our Victron Energy Multiplus-II case ground with 6 AWG wire. This was not correct. We are feeding the DC power to our MP-II from the Lynx Distributor via 4/0 cable. This means we need to use at minimum 2/0 wire for the case ground.
ABYC recommends that the case ground is no smaller than 1x size down from main current carrying conductor.
Do you know why they wouldn't just ground the case to the battery negative wire that's already there and/or could you just tie those two together with a couple of inches of wire? I imagine there's a good reason why they don't , but I don't understand it myself. thanks
I do not, I would have to refer you to your Victron Dealer or Victron community forums. I find it an interesting and valid question.
Tha would be because the inverters have their own internal ground lift from the neutral which cime in effect when the grid is connected by providing it's own return path, conversely, when in stand alone , to he inverter's relay connects to be internal newtral offering a safe return path to the ground rod
Currently fighting the case ground on my multiplus II. And bonus I am out of spots to ground my case grounds.
Hi. Note how I combined case grounds for my MPPTs in the MPPT video to save a space; but I'm not sure I would combine the MPII with anything! You can ground it to the end of the neg bus bar on a post there vs on the post in the middle potentially, if you're using Lynx Distributors?? Please check with your Victron vendor or an EE if you have difficult wiring questions.
@VanTransitions will do. I am using the lynx distributor and the lynx shunt. I was in good shape till I realized I had to run the chassis ground after the shunt for it to work properly. Thinking I might have to add an extra bussbar just for grounds!
There is a slight conflict of info here, first we hear that the earth cable must be one size down from the battery cables then the same difference is related to the inverter cables. Now Victron Wiring Unlimited clearly specifies that the Grounding cable must be able to carry at least the same current as the battery fuse rating but does not specify the size of the inverter ground cable. Also, the inverter ground connection does not offer many options over a certain size because it only carries a 6mm stud/nut. Confusing 🤔
My system chassis ground will match my battery cables at 4/0, which is also the same cable size from my Lynx Distributor to the MPII. My case ground for the MPII goes to the neg bus (middle stud) on a Lynx Distributor. In my case I made the case ground 2/0 as a 4/0 lug simply won't go through the hole in the MPII case. My Victron dealer gave a thumbs up to my schematic.
@@VanTransitions I understand and that matches my way of thinking too, unfortunately, Victron only seem to state that the size of the conductor needs to be at least enough to carry the current out which would imply the AC current, that is what confused me. Thank you for your reply 🙏
You're welcome. Reach out to your dealer and Victron support forums to see if you can get further opinions and hopefully clarity!
@@9111logic Wiring Unlimited clearly states, "... The DC ground cabling should have a sufficient thickness to be able to
carry a fault current at least equal to the *DC* fuse rating. ..." DC is the battery. It does not state "AC Current". And Victron is *not* the authority for grounding or wire size. You Local Zoning Inspector is. Follow the rules per NEC or ABYC.
Does the case ground from Multiplus attach to the RV frame?
If I have a 24V Multiplus, will the ground interfere with the existing trailer/camper 12V LED factory lights (each individual 12V light is grounded to frame also)?
For me the MP II is grounded to the Lynx Distributor which grounds the entire system to the van chassis. You can see that here ua-cam.com/video/myLpukMa35E/v-deo.html
24V and 12V don't play well together without voltage conversion so you will need to know how your trailer/camper existing 12V lights and electric system are configured to know if there will be any interference, especially if both are grounded to the same chassis.
Shouldn't that be 6AWG? Lower number, thicker cable.
The wire for the case ground? See video description. 6AWG is way too small, thus this video to correct that. 6AWG, 4AWG, 2AWG, etc. 0/0, 1/0, 2/0, 4/0 are examples of smaller to larger cables (left to right). 4/0 = 4 ought
When I read my Multiplus II manual, it says to use two 1/0 cables for runs under 5 meters, and two 2/0 cables on runs over 5 meters. You are using one 4/0 connection on your Multiplus II. This does not have the ampacity of two 1/0 cables.
Hi. 4/0 is larger than 1/0, therefore carries greater amps. Please have your drawing/plans approved by your Victron Dealer or an Electric Engineer to make sure you do not undersize any wires in your system.
@@VanTransitions I am an electrical engineer. 1/0 has a max ampacity of 170 amps at 90C. 4/0 has a max ampacity of 260 amps at 90C. When you run two pair of 1/0, it gives you 2 x 170 amps = 340 amps. This exceeds a single 4/0 run by 80 amps. This is why Victron put two positive and two negative lugs on your Multiplus II.
Please consult your Victron Multiplus II installation manual to verify the correct wiring instructions.
You refer to section 4.2. www.victronenergy.com/upload/documents/MultiPlus-II_12V-24V_3kVA_2x120V/32424-MultiPlus-II___Quattro-II_120V-230V-pdf-en.pdf "In order to utilize the full capacity of the product, batteries with sufficient capacity and battery cables with sufficient cross-section should be used. The DC cables must be copper and rated 90oC (194oF)."
This is not a hard set in stone "rule". There are options. www.victronenergy.com/upload/documents/Quick-Install-Guide-MultiPlus-II-12V-3kVA-2x120V-EN(lowres).pdf Here frame 4 only shows 1 +/- pair wired with a fuse directly to the battery while frame 9 and 10 show 2 pair but no specific indication of a fuse or what the other end is connecting to. Ultimately my choice of 1 pair of 4/0 "may" limit my system from full capacity according to the header of 4.2, but it isn't wrong. What would be wrong would be if I put 4AWG wires instead of 4/0.
@@VanTransitions That makes sense. There are so many interpretations of Victron's wiring instructions.
Your chassis ground dilemma is a case in point. In my MP II 2x120 instruction, it says to use 4mm(sq) wire for the ground. That is equivalent to 12 AWG. I've seen other drawings that go all the way from 4/0 (which won't fit) to no chassis ground at all.
I appreciate your detailed response and I read it the same way.
Oh my, I hope that's a misprint and anyone reading this does not put a wire that small on their ground. Do not put 12AWG on your ground! (had to say it) I went up from 6AWG to 2/0 in this correction, and some still say I should have done 3/0. And, I've expressed the same as well, a 4/0 lug doesn't fit through the hole in the chassis to get it to the ground stud. I would have done that just for already having the wire and lugs on hand. All the best.
I am building a system and was using a 6awg wire to ground the multiplus case as well; looks like that needs to change. However, now I'm a little more confused. What I am building is a small system for my home, so I also had a ground wire (6 AWG) connected to the negative terminal of my bus bar that goes to the physical ground of my home (basement floor). Is this incorrect?
In my van based system, my chassis ground is 4/0 matching the largest wires in my system. 6awg seems small, but I don't know the size of your system and I'm not an electrical engineer. If your components are Victron, work with your distributor, or consult an electrician.
@@VanTransitionsthank you
I search this subject ...isnt 3/0 one size down from 4/0
@powerbanksrb - Yes, yes it is ...
There is a little confusion here. There is the difference between the MP-II chassis ground and the system chassis ground to the van. In that regard, I have 4/0 from my batteries to my Lynx Distributor AND 4/0 on the neg to the van for chassis ground.
3/0 is LARGER than 4/0. 2/0 is LARGER than 3/0 etc.
when working with wire numbering is the reverse of what we’re accustomed to thinking.
Hi. The numbering (smaller number is larger wire) is for AWG, not for Ought.
Wire sizing is smaller number is larger wire. Thus a size down from #4 would be #6AWG. A rule of (electrical) thumb with ALL grounding wires, whatever the application) is a size smaller than your hot and neutral leads. It won’t hurt to have gone larger, just not two or more sizes smaller. You have it wired in so you might as well leave it. It won’t hurt. Just a waste of money.
Hi. The 6awg here wasn't nearly a big enough wire, neither would 4awg. I revisit this in my "ground... corrected" video.
He is referring to 4/0 AWG not 4 AWG cable, which would size down to a 2/0 AWG cable
What happened to 3/0? (95 mm2)
Still think you are ok but abyc might not…
I questioned my Victron dealer on this heavily as I am not an EE. On more than 1 response, they restated I was OK and quoted the ABYC standards. I get your point though.
I don't have any 3/0 cable or lugs to test, but it will probably fit, very tightly... the 4/0 lugs I have will not.
@@VanTransitions no worries! I’m at 25.6v so am able to use 2/0 and 1/0. I’ve seen 3/0 but it’s pretty rare-probably pricey, too
Enjoy your channel. Nice work
thank you. so much more to learn and share through the process!
So if I don't have a ground to the chassis (5th Wheel), would this cause the victron to shut down when I turn on the A/C?
Hi. Your question is a bit vague. You need to be properly fused and grounded. You may want to run your electric diagram by your Victron dealer or contact Victron support either via your dealer or direct if you are having issues with Victron equipment.
Hi, i wonder if you can advise me please. You seem to be from the very few on ebay that insists on safety with grounding, which is imperative, i think. There are so many chaps that use lethal power of 240v and do not figure out the importance of grounding and many others that are trying to sell something.
I need to use my lifepo4 24v battery bank on my caravan , this is in UK , for induction hobs only , as fridges and other tools are running on another dedicated 24v battery bank and i want your opinion how to ground the 24v 8000w surge inverter. I have found out through videos that, if only one class 1 item is used in the inverter the risk of electro sock is minimal, as no circuit, but if you add 2 class 1 devices , like a kettle on top of an induction hob, powered at same time then you need a complex grounding diagram to avoid lethal shock if there is a fault, as typical rcd circuits will not work as there is no reference.
So should i add a ground or not in a standard chinese 4000/8000w inverter or not , the chinese company says no need for that. Should i go for Victron instead and split phase, i am in UK so i ll need 240v. Should i only use one class 1 device at a time with my 24v inverter , if this is the safer way i ll do it. I will isolate the rest of the mains of the caravan i can make a dedicated circuit , i need only the hobs mainly to avoid gas bottles, when i sue the caravan, but i can not find answers about grounding.
It is more than obvious when you watch ebay clips that there are many chaps doing really risky things, so you can not trust any thing you watch actually.
Kind regards
Regards
I recommend you consult your manufacturer and an Electrical Engineer (certified electrician) for clarity.
Does your Victron multi plus come bonded or unbonded?
Apparently, a lot of other inverters are either bonded or unbonded at the manufacture !
I would refer you to Victron documentation for that question.
victron multiplus 2 in some europe coutries usualy comes NOt bonded but i m not electrician and cant figure out nether mine if it is bonded or not,,,!!!! i hope there will be a safe way because there are thousands of them already running and probably with not a clue of stats of earth and ground extra safety!
Sorry but you are wrong here. Literally just used 4/0 for chassis ground (per recommendation if using the same for loads) and it fit fine in the Multiplus II
Wrong based on what set of facts and standards?
@@VanTransitionsI just ran the 4/0 through the 4 inch opening directly to the right of grounding opening.
This could work if you only have 1 pair of 4/0 for pos+ and neg- providing power to the MPII. If you are running 2 pair I imagine that hole is quite full? Also, did you add a 90 degree lug? That may be another way around the hole directly meant for the ground being too small for 4/0 going straight in.
CORRECTION Pinned to Previous INCORRECT video?
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