Connecting galvanic isolator and earth

[bigcol]

Hi 

 

I am going to be onecting up a new galvanic isolator up today

qyestion can I at same time use the earth feed to bond to the hull

or is this a completely daft stupid question.

new build, no engine at the moment

but thought of as wiring the isolator up, is bonding the hull to the earth cable the right way.

Is it a must to have earth bonded to the hull

 

many thanks in advance

[Tony Brooks]

From what Gibbo told me the isolator in effect goes in the shoreline feed into the boat, in the earth line. Then the now isolated earth runs to whatever it needs to so could be the hull but if there is a fancy inverter it MIGHT need to go there first but check the manual.

[Sea Dog]

Just so you're absolutely clear: the earth from shore should go directly to the isolator and have nothing bonding it to the hull - there are shore connection sockets which also bond to the hull, so ensure this isn't the case.  BSS and RCD both say that there must be a bond to the hull from the AC earth. This has to be on the boat side of the isolator to for the isolator to work. 

 

 There should be just one AC earth bond and it should be to its own dedicated stud, which ought to  be next to the DC negative ground to the hull. Put it somewhere easy to access and see when your build is complete - I used the engine bearer.  It should not  matter where it goes to the hull from (but see Tony's note above), but convention usually has it going from the AC consumer unit.  If there's going to be a shore supply connected in before the AC consumer unit is fitted, fit a temporary bond and remove it when you complete the work.

 

 

[Jen-in-Wellies]

Furrher to Sea Dog's reply. The reason for the AC hull earth connection being at a different, but nearby point to the DC one is that if a single earth connection stud failed and then an AC fault occured, all your DC equipment would be at mains voltage ??.

 

Jen

[WotEver]

Put simply...

Shore power earth to GI.

GI earth along with shore power L & N to Consumer Unit

4mm² cable from Consumer Unit earth busbar to hull bonding point. 

Edited October 5, 2018 by WotEver
Clarity

[bigcol]

Thanks for your advice fellas

will be fitting the Gi tomorrow

 

so what is the other box for, what does it do lol

 

col

 

 

Is the top photo a Gi ?

metions DC?

[Alan de Enfield]

2 minutes ago, bigcol said:

 

 

so what is the other box for, what does it do lol

 

col

 

 

 

 

Unless you plan to go on to salt water and fit Zinc anodes - possibly nothing ?

Maybe its to stop your anodes 'wearing away' ?

 

Inland waterways (fresh water) uses magnesium anodes, NOT zincs.

[Sea Dog]

The "Zinc Guard" appears to be the commercial name of a regular galvanic isolator, probably named that because it's aimed at the marine leisure boat market where hulls are GRP and the problem is "dezincification" of bronze fittings rather than metal hull corrosion.  Does the same job though, I'd suggest.

[WotEver]

10 minutes ago, bigcol said:

Is the top photo a Gi ?

metions DC?

Yes, the ZincGuard is a GI.

 

The other box is a battery equaliser of some kind. My first thought is that this second box is snake oil. Can you give us a make and model number?

[Tony Brooks]

16 minutes ago, bigcol said:

Thanks for your advice fellas

will be fitting the Gi tomorrow

 

so what is the other box for, what does it do lol

 

col

 

 

 

 

 

Is the top photo a Gi ?

metions DC?

 

I agree that it is a GI. Ignore the DC negative bit because I think it is because some authorities say connect both the AC earth & DC negative bond to the same stud. Don't, do ass advised  above for the reason give.

 

The lower box looks to be as if it is a charger for charging a 12V battery from a 24V alternator, or possibly both the 12 & 24V banks from one 24 volt source but can't be sure because the label is obstructed by cables.

 

Edited to add - Looks like it only has a 10 amp output but probably OK for charging a 12V start battery from a 24 volt alternator.

Edited October 5, 2018 by Tony Brooks

[bigcol]

Thankyou all

forums has been and still is working for me

 

just made another small one of donation to site.

many thanks again 

‘grateful forum member

[Chewbacka]

According to Mr Google it is an old Vanner smps (power supply) for running 12v kit from a 24v battery bank with a max load of 10amps.

 

so presumably yours is a 24v boat and his powers something like a car radio etc?

 

if you want to know more google “vanner 60 10b”

Edited October 5, 2018 by Chewbacka

[bigcol]

Yes new boat has a 24v battery bank

couple of items on board is 12 volt those have 24v and 12v panels installed 

panel left 12v. Middle panel 24v and right hand panel 240 mains

[Sea Dog]

37 minutes ago, bigcol said:

Yes new boat has a 24v battery bank

couple of items on board is 12 volt those have 24v and 12v panels installed 

panel left 12v. Middle panel 24v and right hand panel 240 mains

Ooh, lots of pretty lights! How posh are you!? 

Hope you they don't dazzle you when going through tunnels as the one green light on my Beta 43's panel tries its best to do that to me.  I really like the NASA BM1display: the shunt wasn't big enough for my needs or I'd has gone that way too. Anyway, it's coming along nicely, isn't it. 

[bigcol]

Slow, lots of heart ache, but yes

Thankyou very much 

[blackrose]

On 05/10/2018 at 09:55, WotEver said:

Put simply...

Shore power earth to GI.

GI earth along with shore power L & N to Consumer Unit

4mm² cable from Consumer Unit earth busbar to hull bonding point. 

 

I just connected an earth cable  from the boat side of the GI to the hull earth stud. I don't see any reason it has to come from the consumer unit if the GI and earth stud are in proximity? It's all the same earth path.

Edited October 6, 2018 by blackrose

[WotEver]

1 hour ago, blackrose said:

 

I just connected an earth cable  from the boat side of the GI to the hull earth stud. I don't see any reason it has to come from the consumer unit if the GI and earth stud are in proximity? It's all the same earth path.

No reason at all, electrically. Wiring from the CU is just a logical way of doing it. Wiring it otherwise can make it more confusing for the next owner wiring in an inverter though, when he reads that ‘the inverter case must be connected to the boat hull’ and he doesn’t realise that it already does so, but it goes via the GI. 

Edited October 6, 2018 by WotEver
Clarity

[bigcol]

On 05/10/2018 at 16:22, Chewbacka said:

vanner 60 10b

This was on the wall, but never used it, 

post 6 on this thread.

yes I admit I don’t help sometimes, but through the forum I get their in the end.

unlike trains run by professionals 

[Detling]

Lovely panels but I hope you can turn the LED indicators off, one at night it will be a bit bright and secondly those LEDs will take about 10mA each a tiny amount for one but you appear to have over 40 lit so 40x10=400mA x 24 hrs= 9.6 amp hours. per day not a lot but significant if off shoreline cruising. Definitely a problem in winter as some days my 600 watts of solar produces less than 10 amp hours.

[BruceinSanity]

On 05/10/2018 at 17:16, Sea Dog said:

I really like the NASA BM1display: the shunt wasn't big enough for my needs

You know you can get a NASA BM2 with a 200A shunt?

[Sea Dog]

2 hours ago, BruceinSanity said:

You know you can get a NASA BM2 with a 200A shunt?

My inverter was rated at 2500va continuous and could manage surge to more (4000va iirc) for coping with starting current. Whilst unlikely I'd ever draw anything like that without a charging source input to mitigate such a high output, I still felt that I ought to have the capacity for it so I went with the 500a Victron. Good unit, but I think the NASA is a better display.