240v earth bonding

[dave mackie]

Can you earth shoreline/invertor 240v cables to hull. Or where is best.

[Tracy D'arth]

4 minutes ago, dave mackie said:

Can you earth shoreline/invertor 240v cables to hull. Or where is best.

Yes, should do.  On separate studs so if one gets pulled off the others are still there, separate from the battery negative connection as well but preferable nearby so that it is obvious to an examiner.

[Tony Brooks]

15 minutes ago, Tracy D'arth said:

o that it is obvious to an examiner.

 

And any future trades person, saves you paying them to look for it.

[Alan de Enfield]

The RCR and ISO 13297  Small craft — Electrical systems — Alternating current installations

 

Requires :

 

4 General requirements

 

4.1 The protective conductor insulation shall be green or green with a yellow stripe. Neither colour shall be used for current-carrying conductors. NOTE The equipotential bonding conductor of the d.c. electrical system (see ISO 10133) also uses green, or green with a yellow stripe, insulation and is connected to various exposed conductive parts of direct-current electrical devices, other extraneous conductive parts and the d.c. negative ground/earth.

 

4.2 The protective conductor shall be connected to the craft's d.c. negative ground (earth) as close as practicable to the battery (d.c.) negative terminal. NOTE If an RCD (whole-craft residual current device) or an isolation transformer is installed in the main supply circuit of the a.c. system (see 8.2), the negative ground terminal of the d.c. system need not be connected to the a.c. shore ground (protective conductor).

 

4.3 For craft with fully insulated d.c. systems (see ISO 10133), the a.c. protective conductor shall be connected to the hull of a metallic hull craft, the craft external ground (earth) or the craft lightning-protection ground plate, if fitted.

 

4.4 Metallic craft hulls shall not be used as conductors.

 

4.5 The protective conductor shall be connected to metallic hulls at a location above any anticipated water accumulation

 

Although it is often suggested on the forum that it is not ideal in case the stud breaks off.

Edited January 13, 2023 by Alan de Enfield

[dave mackie]

Cheers Tracy, I'll fix it too bulkhead. It's already got a earth point there but it's been secured with a self tapping screw by the previous owner and it's loose !!! And I've been told that I have an earth leak on boat so I'm hoping making a decent connection will cure prob. cheers

[Tony Brooks]

1 minute ago, dave mackie said:

Cheers Tracy, I'll fix it too bulkhead. It's already got a earth point there but it's been secured with a self tapping screw by the previous owner and it's loose !!! And I've been told that I have an earth leak on boat so I'm hoping making a decent connection will cure prob. cheers

 

I very much doubt that it will. I don't see how a loose bond point would create an earth leak, in fact it would tend to minimize it - all depending upon what you mean by an earth leak and where/how it was measured/identified.

[GUMPY]

You do NOT want to connect the shore line directly to the hull this will lead to a dissolving  boat !

However what you should do is connect from the on board consumer unit to the hull.

This will be after the Isolation Transformer or Galvanic isolator which should prevent your boat dissolving.

 

[PaulD]

1 hour ago, Loddon said:

You do NOT want to connect the shore line directly to the hull this will lead to a dissolving  boat !

However what you should do is connect from the on board consumer unit to the hull.

This will be after the Isolation Transformer or Galvanic isolator which should prevent your boat dissolving.

 

Victron tell you to only connect the neutral on the boat side of the isolation transformer to the hull earth. I think this has created a lot of debate in the past as there is a risk of a fault creating a voltage between the boat and the shore which could electrocute you when boarding - as well as dissolving the boat.

Edited January 13, 2023 by PaulD
Clarification

[Alan de Enfield]

I guess the question comes down to - who do you believe, & whose guidance do you take ?

 

If it is a choice between, the manufacturers installation instructions, the ISO standards and the RCD / RCD  or, some unknown 'random bloke' on the internet I know which I'd choose.

 

IF, IF, there was to be any problem with you being electrocuted, or your boat fizzing away, which course of action would the Coroner, or the insurance company, consider to have been 'industry best practice' ? 

 

 

Edited January 13, 2023 by Alan de Enfield

[Tractor]

As I understand the connection:

For a boat fitted with an isolation transformer, the secondary side of the transformer, neutral and earth should be connected together and bonded to the hull. The primary side, neutral and earth must not be connected to the hull. Isolating the boat from the shoreline.

 

If fitted with a galvanic isolator, the single earth connection between boat and shore supply must pass through the galvanic isolator.

[Chewbacka]

56 minutes ago, Alan de Enfield said:

I guess the question comes down to - who do you believe, & whose guidance do you take ?

 

If it is a choice between, the manufacturers installation instructions, the ISO standards and the RCD / RCD  or, some unknown 'random bloke' on the internet I know which I'd choose.

 

IF, IF, there was to be any problem with you being electrocuted, or your boat fizzing away, which course of action would the Coroner, or the insurance company, consider to have been 'industry best practice' ? 

 

 

I know which I chose as well, but sadly some will chose whoever tells them what they want to hear.  Follow the regs, they are there for a reason

[MtB]

2 minutes ago, Chewbacka said:

Follow the regs, they are there for a reason

 

Indeed, and it would be great if they would tell us what the reason is, in some cases...!

 

 

 

 

 

[BEngo]

27 minutes ago, MtB said:

 

Indeed, and it would be great if they would tell us what the reason is, in some cases...!

 

 

 

 

 

The reason is : "Because."

 

N

[Alan de Enfield]

22 minutes ago, MtB said:

 

Indeed, and it would be great if they would tell us what the reason is, in some cases...!

 

 

 

 

 

 

 

Have you ever known a BS or ISO standard justify or explain their reasoning for requiring some feature ?

But why should they ?

 

Why for example has the RCR / ISO standard chosen these tensile strengths for cable teminations, over any others ?

 

 

 

 

 

 

[dave mackie]

Was told by an electrician that my boat  is causing the whole marina to trip out !!!!! I've been on marina for 1 1/2 yes without a problem. Been on shoreline all this time and only have a WiFi router and victron smart charger running which have been on constantly for the whole period. I'm finding it strange!!!!

 

[MtB]

2 minutes ago, dave mackie said:

Was told by an electrician that my boat  is causing the whole marina to trip out !!!!! I've been on marina for 1 1/2 yes without a problem. Been on shoreline all this time and only have a WiFi router and victron smart charger running which have been on constantly for the whole period. I'm finding it strange!!!!

 

 

Oh that's tricky. I'd suggest one boat (yours or anyone's) tripping out the whole marina means the marina wiring is poorly designed. 

 

I'd suggest your bollard should trip out first, not the whole marina. IF it is your boat at fault in the first place, which I'm inclined to doubt. 

 

 

[Tractor]

If the electrical distribution is competent, this is not possible.

 

[GUMPY]

2 hours ago, PaulD said:

Victron tell you to only connect the neutral on the boat side of the isolation transformer to the hull earth. I think this has created a lot of debate in the past as there is a risk of a fault creating a voltage between the boat and the shore which could electrocute you when boarding - as well as dissolving the boat.

Victron wire their iso transformers wrongly.

They didn't take the primary earth to the transformer core but use the secondary earth. This means that in the case of a very unlikely breakdown of the primary windings with a short to the core the whole boat goes live.

Gibbo tackled them about this 15years or so ago but they brushed it off as inconsequential 

[GUMPY]

It's very simple to wire an ISO transformer.

Shore L&N to primary L&N of the transformer.

Shore Earth to transformer core/earth

Secondary L&N of the transformer to L&N of the boat.

Boat Earth connected to Secondary N of the transformer and to hull of boat.

No arguments any other way is wrong.

[Alan de Enfield]

3 minutes ago, Loddon said:

Victron wire their iso transformers wrongly.

They didn't take the primary earth to the transformer core but use the secondary earth. This means that in the case of a very unlikely breakdown of the primary windings with a short to the core the whole boat goes live.

Gibbo tackled them about this 15years or so ago but they brushed it off as inconsequential 

 

 

Over the last  'X' years how many examples of this happening have been recorded ?

 

Is this another case of 'worrying about nothing' ?

[PaulD]

3 minutes ago, Loddon said:

Victron wire their iso transformers wrongly.

They didn't take the primary earth to the transformer core but use the secondary earth. This means that in the case of a very unlikely breakdown of the primary windings with a short to the core the whole boat goes live.

Gibbo tackled them about this 15years or so ago but they brushed it off as inconsequential 

I see that the current smart gauge website has removed Gibbo’s pages about isolation transformers. 

[GUMPY]

It's for this reason you can't have a transformer in a metal box on the boat

Here is an example of how to wire 230v with a transformer.

230vAC NEW 2_0.pdf

Edited January 13, 2023 by Loddon

[GUMPY]

5 minutes ago, PaulD said:

I see that the current smart gauge website has removed Gibbo’s pages about isolation transformers. 

Still there

 

http://www.smartgauge.co.uk/iso_wire.html

[Tony Brooks]

37 minutes ago, dave mackie said:

Was told by an electrician that my boat  is causing the whole marina to trip out !!!!! I've been on marina for 1 1/2 yes without a problem. Been on shoreline all this time and only have a WiFi router and victron smart charger running which have been on constantly for the whole period. I'm finding it strange!!!!

 

 

So it does not trip your boat's RCD (which just might be incorrectly wired), does not trip your bollard RCD (that should be correctly wired), but does trip the whole marina. I find it so strange it is getting on for unbelievable.

[cuthound]

1 hour ago, Loddon said:

It's very simple to wire an ISO transformer.

Shore L&N to primary L&N of the transformer.

Shore Earth to transformer core/earth

Secondary L&N of the transformer to L&N of the boat.

Boat Earth connected to Secondary N of the transformer and to hull of boat.

No arguments any other way is wrong.

 

That is exactly how BT wired their isolation transformers (except for the bit about wiring the secondary neutral to the hull, obviously).