Victron multiplus case earth bonding?

[Emma b]

Hi could anyone please clarify whether or not my multiplus casing should be bonded to the hull or not please?

There is a hull earth from the 240 consumer unit and a galvanic isolator is fitted .

It didn't have a case earth but I fitted one recently.

The reason for asking is when, inadvertently I glanced a metal caged lead light on the battery positive terminal, I got an arc which surprised me.

Simon

[Robbo]

Relevant section in the manual....

 

b ) Phoenix Multi / MultiPlus: the output neutral wire will automatically be bonded to the chassis (with the output ground relay, see appendix) when no external AC source is available (backfeed / safety relay open and product runnig in inverter mode, see appendix). When an external AC source is provided, the ground relay opens before closure of the backfeed / safety relay. Once closed, the backfeed / safety relay ensures that the neutral to ground bond is provided by the external AC source. This is to ensure proper functioning of a GFCI to be installed in the AC output of the Multi/MultiPlus.

- In a fixed (for example terrestrial) installation an uninterrupted chassis ground may be provided by the AC input ground wire.

- In case of a mobile installation (connection to input AC with a shore power cord), the ground connection is lost when the shore power cord is unplugged. In this case the chassis of the product or the on - board section of the input ground wire must be connected to the frame (of the vehicle) or the ground plate or hull (of a boat).

- Marine applications: due to the potential for galvanic corrosion it is in general not acceptable to connect the shore side ground to the ground plate or hull of the boat. The proper and safe solution is to install an isolation transformer.

Edited December 18, 2016 by Robbo

[nicknorman]

It is not in the least bit surprising that you got an arc when you brushed the metal lead lamp onto the battery +ve terminal. The battery negative terminal should be bonded to the hull. The AC earth wire should be bonded to the hull. Therefore the earth on the light should be connected to battery -ve and if you touch an earth wire to the battery +ve terminal one would certainly expect and hope that you would create a short circuit / arc.

 

I wouldn't modify the Combi by adding additional earths direct to hull as you will create a possible earth or negative circuit/loop via the hull. The Combi should be earthed by the lead going to the consumer unit and that in turn should (and obviously does) have a connection to hull at a single point.

[Emma b]

Thank you for that clear explanation nick. I will remove the "additional " earth bond I fitted and shall sleep easier tonight.

Simon

[Robbo]

Thank you for that clear explanation nick. I will remove the "additional " earth bond I fitted and shall sleep easier tonight.

Simon

the ground connection is lost when the shore power cord is unplugged. In this case the chassis of the product or the on - board section of the input ground wire must be connected to the frame (of the vehicle) or the ground plate or hull (of a boat)

Note the chassis still needs to be grounded, this will need to be from the chassis if the input cable from the shore line isn't grounded to the hull (preferably after a galvanic isolator or isolation transformer). If just your consumer box earth is connected to the hull then the chassis isn't grounded unless your shore cable ground goes to the consumer box as well (and the to the hull) Edited December 18, 2016 by Robbo

[Emma b]

Hi Rob just to confirm the earth from the shore line and after the galvanic isolator goes to the earth bus inside the consumer unit and then another earth runs from the same earth bus bar to the hull.

In addition I earthed the Victron casing as well to the hull. The casing wasn't earthed before.

Regards Simon

[nicknorman]

Note the chassis still needs to be grounded, this will need to be from the chassis if the input cable from the shore line isn't grounded to the hull (preferably after a galvanic isolator or isolation transformer). If just your consumer box earth is connected to the hull then the chassis isn't grounded unless your shore cable ground goes to the consumer box as well (and the to the hull)

Well actually no, the chassis doesn't necessarily need to be grounded. It may be a double insulated product. If it does need to be grounded (because the product isn't double insulated) this will be taken care of internally. Provided either the incoming or outgoing Combi connections include an earth lead that is connected to hull (which in the OP's case, it clearly is, via the consumer unit) then the chassis will, if it needs to be, be earthed.

 

I think your last sentence is a bit confusing or wrong since the shore line has nothing to do with it. What is relevant is a connection from the boat's mains distribution system earth lines, to the hull. If shore power happens to be plugged in then sure, the incoming earth should be connected to hull via a GI. But of course not if it is via an IT. But even with no shore power, the mains distribution earth should be connected to hull.

[Robbo]

Well actually no, the chassis doesn't necessarily need to be grounded. It may be a double insulated product. If it does need to be grounded (because the product isn't double insulated) this will be taken care of internally. Provided either the incoming or outgoing Combi connections include an earth lead that is connected to hull (which in the OP's case, it clearly is, via the consumer unit) then the chassis will, if it needs to be, be earthed.

I think your last sentence is a bit confusing or wrong since the shore line has nothing to do with it. What is relevant is a connection from the boat's mains distribution system earth lines, to the hull. If shore power happens to be plugged in then sure, the incoming earth should be connected to hull via a GI. But of course not if it is via an IT. But even with no shore power, the mains distribution earth should be connected to hull.

Please read this part of the manual....

 

In case of a mobile installation (connection to input AC with a shore power cord), the ground connection is lost when the shore power cord is unplugged. In this case the chassis of the product or the on - board section of the input ground wire must be connected to the frame (of the vehicle) or the ground plate or hull (of a boat).

[WotEver]

Please read this part of the manual....

 

In case of a mobile installation (connection to input AC with a shore power cord), the ground connection is lost when the shore power cord is unplugged. In this case the chassis of the product or the on - board section of the input ground wire must be connected to the frame (of the vehicle) or the ground plate or hull (of a boat).

Please understand Nick's point. That Earth connection for the chassis is supplied by the Earth bond from the consumer unit.

 

Edited for tryping

Edited December 18, 2016 by WotEver

[nicknorman]

Please read this part of the manual....

In case of a mobile installation (connection to input AC with a shore power cord), the ground connection is lost when the shore power cord is unplugged. In this case the chassis of the product or the on - board section of the input ground wire must be connected to the frame (of the vehicle) or the ground plate or hull (of a boat).

Firstly, can I just say that I hate Victron manuals! Anyway the manual (which manual are we talking about, there are so many for the different variants of the Multiplus?!) on the one hand implies that the input and output earths are connected together (which they surely must be) and yet as you point out it specifies that the input ground wire must be grounded. I think it is just lost in translation.

 

I've never had a Victron Combi but surely the chassis is connected to both the PE terminals on the AC connection block? And if the cable going to the consumer unit is 3 core and the consumer unit earth is connected to hull then the requirement is met.

[Robbo]

Please understand Nick's point. That Earth connection for the chassis is supplied by the Earth bond from the consumer unit.

 

Edited for tryping

If only the output AC ground is connected to the consumer unit (which connects to the hull, etc). Then the chassis won't be grounded when there isn't a input AC source, so either the chassis needs to the extra ground cable or the input AC ground needs to go to the consumer unit/hull.

Firstly, can I just say that I hate Victron manuals! Anyway the manual (which manual are we talking about, there are so many for the different variants of the Multiplus?!) on the one hand implies that the input and output earths are connected together (which they surely must be) and yet as you point out it specifies that the input ground wire must be grounded. I think it is just lost in translation.

 

I've never had a Victron Combi but surely the chassis is connected to both the PE terminals on the AC connection block? And if the cable going to the consumer unit is 3 core and the consumer unit earth is connected to hull then the requirement is met.

It does seem daft, and I can't see why it's not a common ground in the unit.

[nicknorman]

So are you categorically saying that the output PE terminal is not connected to the Combi's case, if so how do you know this and how do you explain the OP's experience?

[Robbo]

So are you categorically saying that the output PE terminal is not connected to the Combi's case, if so how do you know this and how do you explain the OP's experience?

Only from what manual says. I can check on my multi if this is the case. The OP stated that the AC input was grounded at the GI so the chassis is grounded.

[nicknorman]

Only from what manual says. I can check on my multi if this is the case. The OP stated that the AC input was grounded at the GI so the chassis is grounded.

I'd be fairly confident the manual is misleading on this point, but it would be interesting if you could physically check for continuity between the 2 PE connections and the case.

[Emma b]

Thanks for this gents it is much appreciated.

I meant the input wiring not shoreline as you picked up earlier.

I could either/also take an earth tapping from the boat side of the galvanic isolator to the hull easily too if appropriate.

Again many thanks and I look forward to clarification

Simon

[nicknorman]

I would have thought your present arrangement was fine, there is just slight doubt because of the wording of the manual. If you have an multimeter with ohms range it will be a simple matter to check if the Combi case is already connected to the hull. I'd be very surprised if it wasn't but if that were the case then yes you could add an earth wire from the hull side of the GI to the hull, preferably to the same point the other earth wire from the CU goes. Then the letter of the manual would be met.

[Keith M]

It is standard practice with both Mastervolt and Victron that the chassis is not bonding to earth in any mode.

 

Keith

[Emma b]

Right Gents. I disconnected the chassis earth and there is continuity present between the Victron case and the hull (earth) when the Victron is operating via the shore line (on charge only) and when disconnected from the shore line (invertor switch selected ) so looks like no need for that extra earth I fitted!

Hopefully that is one query solved many thanks again.

Simon

[elastic]

I know this thread is quite old but I had the same question coming up while checking my electric installation and finally found this answer to it: https://www.jamestowndistributors.com/userportal/document.do?docId=1014

thought I should add this here ...

 

[WotEver]

31 minutes ago, elastic said:

I know this thread is quite old but I had the same question coming up while checking my electric installation and finally found this answer to it: https://www.jamestowndistributors.com/userportal/document.do?docId=1014

thought I should add this here ...

It adds nothing. 

The AC supply should be bonded to the hull from the Consumer Unit. If it is, then so is the Victron chassis. If you really want to run another Earth wire from the chassis to the bonding point knock yourself out, but it's pointless. 

[Emma b]

Hi elastic,

Thanks for that and yes good to know.  All has been fine since so good news!