Generator

[nb Innisfree]

26 minutes ago, F DRAYKE said:

And how would you do that?

If it's an auto E/N disconnect when power is coming through Shorepower inlet then there's nothing to do, if not then it's either a manual disconnect or a permanent one, either way it has to be disconnected or the onshore genny RCD will trip. 

 

You don't have to link earth and neutral at the genny end of the shorepower lead but there will no RCD protection upstream of the boat RCD

Edited August 30, 2018 by nb Innisfree

[Drayke]

2 minutes ago, nb Innisfree said:

If it's an auto E/N disconnect when power is coming through Shorepower inlet then there's nothing to do, if not then it's either a manual disconnect or a permanent one, either way it has to be disconnected or the onshore genny RCD will trip. 

OK, I think I understand. Re you saying that if the neutral and earth wires at the back of the inlet socket on the boat have separate wires going to the distribution board then that's ok?

[nb Innisfree]

31 minutes ago, F DRAYKE said:

OK, I think I understand. Re you saying that if the neutral and earth wires at the back of the inlet socket on the boat have separate wires going to the distribution board then that's ok?

E/N link has to be upstream of an RCD, if for instance you make the link at the genny then an RCD needs to be downstream of that i.e. E/N link - RCD - boat shorepower inlet. Boat E/N link could be anywhere between SP inlet and onboard RCD. 

 

RCD detects a difference in current between live and neutral if that difference has leaked away (probably through someone) along earth wire upstream of RCD via E/N link. 30 mA is safe trip current though Gibbo pointed out 'electric shock drowning', recognised in the USA but not here. Apparently this can disable muscles of someone in the water at levels below 30mA, I believe 5mA trip RCD is more common in marinas in USA though I have no proof of that. 

Edited August 30, 2018 by nb Innisfree

[nb Innisfree]

https://www.boatus.com/seaworthy/magazine/2013/july/electric-shock-drowning-explained.asp

 

Doesn't bode well for 30mA RCDs

Edited August 30, 2018 by nb Innisfree

[blackrose]

There's some confusion here. Most portable suitcase generators have a floating earth and N - E is not bonded, so connecting an earth lead to the steel armco on the bank won't do anything. The first thing to do is find out whether the generator has a floating earth or not. 

 

If it does then either N-E can be bonded at the output of the generator (or dedicated cable which should be labelled as such and not used for any other purpose) and the earth stud/chassis of the generator should be connected to an earth spike or equivalent. This arrangement will allow the boat's RCD to function, but there will be no protection from the N-E bond you've created to the boat's breakers. If you do this the boat's AC system must be hull - earth bonded (it should be anyway even if you don't have a generator). 

 

The other option is to plug straight from the generator into the boat without altering anything and simply rely on the generator's floating earth rather than the boats RCD. But a floating earth is generally used when a generator is used to power a single piece of equipment rather than an entire ring mains with multiple outlets. 

 

https://petepowerblog.wordpress.com/2017/10/24/earthing-your-generator-floating-live-and-neutral-or-neutral-bonded-to-earth/
 

Edited August 31, 2018 by blackrose

[cuthound]

7 hours ago, nb Innisfree said:

https://www.boatus.com/seaworthy/magazine/2013/july/electric-shock-drowning-explained.asp

 

Doesn't bode well for 30mA RCDs

 

Interestung article, but the it does say that European, Australian and New Zealand a.c. supplies have had ground fault protection (rcd's) for over 30 years and no recorded fatalities due to ESD.

 

A 5mA RCD is likely to result in many, many nuisance trips, so the 30mA domestic and 100mA industrial rcd's are a compromise between providing human safety and minimising nuisance tripping.

[Markinaboat]

Found this earlier post that also makes interesting reading.

 

https://www.canalworld.net/forums/index.php?/topic/83118-generator-earthing/

[cuthound]

5 hours ago, blackrose said:

There's some confusion here. Most portable suitcase generators have a floating earth and N - E is not bonded, so connecting an earth lead to the steel armco on the bank won't do anything. The first thing to do is find out whether the generator has a floating earth or not. 

 

If it does then either N-E can be bonded at the output of the generator (or dedicated cable which should be labelled as such and not used for any other purpose) and the earth stud/chassis of the generator should be connected to an earth spike or equivalent. This arrangement will allow the boat's RCD to function, but there will be no protection from the N-E bond you've created to the boat's breakers. If you do this the boat's AC system must be hull - earth bonded (it should be anyway even if you don't have a generator). 

 

The other option is to plug straight from the generator into the boat without altering anything and simply rely on the generator's floating earth rather than the boats RCD. But a floating earth is generally used when a generator is used to power a single piece of equipment rather than an entire ring mains with multiple outlets. 

 

https://petepowerblog.wordpress.com/2017/10/24/earthing-your-generator-floating-live-and-neutral-or-neutral-bonded-to-earth/
 

 

I forgot many portable generators are inverter generators with a floating earth.

 

I am more used to working with commercial generators with outputs between 100kVA and 3MVA, all of which use rotating coil alternators and need a dedicated earth connection.

 

 

[nb Innisfree]

25 minutes ago, cuthound said:

 

Interestung article, but the it does say that European, Australian and New Zealand a.c. supplies have had ground fault protection (rcd's) for over 30 years and no recorded fatalities due to ESD.

 

A 5mA RCD is likely to result in many, many nuisance trips, so the 30mA domestic and 100mA industrial rcd's are a compromise between providing human safety and minimising nuisance tripping.

.If there's no recorded ESD fatalities it doesnt mean there aren't any, I think there are none because ESD isn't recognised so isn't considered instead it's put down to other causes, i.e. heart failure etc. I believe it can't be detected in a post mortem. 

 

ETA: Probably best to avoid immersion near freshwater marinas. 

Edited August 31, 2018 by nb Innisfree

[nb Innisfree]

The point is that ESD isn't necessarily death directly from electrocution, its secondary from the inability to swim or stay afloat because of electrical disruption of muscular activity. Below 30mA is 'safe' if you're out of the water but not if you're immersed in it. 

 

ETA: emphasing 'safe' which is subjective, ultimately no level of current can be considered safe. 

Edited August 31, 2018 by nb Innisfree

[nb Innisfree]

https://www.amazon.com/Shock-Alert-42500/dp/B06XDGC9B4

[LadyG]

On 30/08/2018 at 08:23, Mike the Boilerman said:

 

Gunwales and gunnels. 

Gunnels are narrow back alleys found in Kilmarnock, for some reason they do not appear in the OED

[Iain_S]

40 minutes ago, LadyG said:

Gunnels are narrow back alleys found in Kilmarnock, for some reason they do not appear in the OED

Probably a corruption/ local variation of "ginnel".

[cereal tiller]

59 minutes ago, LadyG said:

Gunnels are narrow back alleys found in Kilmarnock, for some reason they do not appear in the OED

Always thought that a Gunnel was a Conical bespouted device used for filling Cannons with Gunpowder?

[cuthound]

Apparently it is a fish.

 

gunnel¹

ˈɡʌn(ə)l/

noun

1. an elongated laterally compressed fish with a dorsal fin that runs along most of the back and reduced or absent pelvic fins. It occurs in cool inshore waters of the northern hemisphere.

[Dr Bob]

3 hours ago, cuthound said:

Apparently it is a fish.

 

gunnel¹

ˈɡʌn(ə)l/

noun

1. an elongated laterally compressed fish with a dorsal fin that runs along most of the back and reduced or absent pelvic fins. It occurs in cool inshore waters of the northern hemisphere.

Cod you be wrong about this?

[TheBiscuits]

28 minutes ago, Dr Bob said:

Cod you be wrong about this?

I wondered that, but it wasn't my plaice to say.

[Dr Bob]

48 minutes ago, TheBiscuits said:

I wondered that, but it wasn't my plaice to say.

A senitment endorsed by my friend Hali. But I am not so sure.

[Alan de Enfield]

18 minutes ago, Dr Bob said:

A senitment endorsed by my friend Hali. But I am not so sure.

Pure GOLD

[Dr Bob]

8 minutes ago, Alan de Enfield said:

Pure GOLD

I thought we were doing sea fish?

[WotEver]

On 30/08/2018 at 21:31, nb Innisfree said:

But you then need to disable earth neutral link downstream from that. 

What ‘N-E link downstream from that’ are you referring to?

On 30/08/2018 at 22:40, nb Innisfree said:

Boat E/N link could be anywhere between SP inlet and onboard RCD

Again... WHAT ‘boat N-E link’?

 

The boat should not have, ever, anywhere, a N-E link. An inverter may have one if required but the boat electrical system should never have one. 

[cuthound]

11 hours ago, Dr Bob said:

Cod you be wrong about this?

 

I don't fin so!

[nb Innisfree]

10 hours ago, WotEver said:

What ‘N-E link downstream from that’ are you referring to?

Again... WHAT ‘boat N-E link’?

 

The boat should not have, ever, anywhere, a N-E link. An inverter may have one if required but the boat electrical system should never have one. 

Sorry, only just returned. Yes I mean the link in an inverter, our Victron was an earlier build which didn't have auto connect so I arranged for a manual one to allow connection to SP. Never got round to making it automatic. 

 

ETA: Just to be clear I arranged a link to enable boat RCD when off SP and on inverter power. 

Edited September 3, 2018 by nb Innisfree

[WotEver]

2 hours ago, nb Innisfree said:

Sorry, only just returned. Yes I mean the link in an inverter, our Victron was an earlier build which didn't have auto connect so I arranged for a manual one to allow connection to SP. Never got round to making it automatic. 

 

ETA: Just to be clear I arranged a link to enable boat RCD when off SP and on inverter power. 

That link should be made at the inverter. So if the inverter is not supplying your 230V then there is no link. 

[nb Innisfree]

1 hour ago, WotEver said:

That link should be made at the inverter. So if the inverter is not supplying your 230V then there is no link. 

Rather than have the Victron upgraded to a later auto version I provided a manual link immediately after the Victron, that way I had the choice of RCD or not when using the Victron off grid.