Fitting 240v now.

Note : Most (read pretty much all) inverters use float so 120v on each P + N so 240v ish total on a single phase install. You will only get a shock should you touch both live and neutral at the same time. There is no earth so cannot be any earth leakage so an RCD does naff all to anything fed via inverter. An RCD will just act as a switch. An inverter mains output should be protected by a fuse (plug in type inverters) or an MCB (hardwired big boys). This will protect over-current.

Same goes for most generators. If you plug a socket tester into the majority of genny’s, the tester will show phase and neutral reverse, that’s not the case, there is just voltage on both the live and neutral conductors.

Be safe!
 
matthewriches said:
Note : Most (read pretty much all) inverters use float so 120v on each P + N so 240v ish total on a single phase install. You will only get a shock should you touch both live and neutral at the same time. There is no earth so cannot be any earth leakage so an RCD does naff all to anything fed via inverter. An RCD will just act as a switch. An inverter mains output should be protected by a fuse (plug in type inverters) or an MCB (hardwired big boys). This will protect over-current.

Same goes for most generators. If you plug a socket tester into the majority of genny’s, the tester will show phase and neutral reverse, that’s not the case, there is just voltage on both the live and neutral conductors.

Be safe!
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Not quite right:
You are right in that you will only get a shock from a floating supply if there are 2 faults (basically making it not floating AND you touching it). However if there is one fault that grounds P or N and you touch the other conductor, the RCD will trip (but only when you touch) not best pleasant, but supposedly able to prevent fatal shock. If both faults are you touching P and N then an RCD wont help.

As for 2 independently wired sockets in a dual gang outlet, I am fairly sure that the regs would go pear-shaped and explode if each were wired to a different phase (just the same as separate sources)
 
Yes, The inverter would have to be neutralised at source for it to trip. This creates the initial fault and then you touching creates the action fault (second). If the inverter was not Earth - Neutral linked then it still won’t trip.

Should we begin discussing double pole isolation as well lol :sleeping: or the dangers of electricity.

2 independently wired supplies in an enclosure is fine if they are labelled, as any 3 phase distro panel. I wouldn’t recommend it in a domestic environment as it just isn’t the done thing lol.

Dougal Tolan said:
Not quite right:
You are right in that you will only get a shock from a floating supply if there are 2 faults (basically making it not floating AND you touching it). However if there is one fault that grounds P or N and you touch the other conductor, the RCD will trip (but only when you touch) not best pleasant, but supposedly able to prevent fatal shock. If both faults are you touching P and N then an RCD wont shelp.

As for 2 independently wired sockets in a dual gang outlet, I am fairly sure that the regs would go pear-shaped and explode if each were wired to a different phase (just the same as separate sources)
Click to expand...
 
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OP has not mentioned if he expects to leave 240vAC power connected to the boat long term. (24/7) for battery charger. This can have serious implications for electrolysis especially if battery charger has a connection, mains earth to battery negative so to engine and underwater gear. A galvanic isolator should be used to protect both your underwater gear and the marina under water iron work. This is connected in series with the incoming earth line or where practical between the ships earth (-ve) and incoming earth. Further I think that any permanent mains type wiring would require a licensed electrician to give a certificate for the wiring.
All this complication means that it is much easier to simply provide portable wiring for short term mains use. But long term mains use gets complicated. olewill
 
Something else to consider, along with the whole bigger picture. Which cable should he use, cable routes appropriate to his vessel and any regulations that may apply to his vessel, mechanical protection that may be required, location of installation, etc, etc, etc....

I don't like to give too much advise online as it can be misinterpreted, "give them and inch" and all that. But one must never assume an inverter will trip an RCD, a lot of stuff coming out of factories are not wired to do so.


William_H said:
OP has not mentioned if he expects to leave 240vAC power connected to the boat long term. (24/7) for battery charger. This can have serious implications for electrolysis especially if battery charger has a connection, mains earth to battery negative so to engine and underwater gear. A galvanic isolator should be used to protect both your underwater gear and the marina under water iron work. This is connected in series with the incoming earth line or where practical between the ships earth (-ve) and incoming earth. Further I think that any permanent mains type wiring would require a licensed electrician to give a certificate for the wiring.
All this complication means that it is much easier to simply provide portable wiring for short term mains use. But long term mains use gets complicated. olewill
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matthewriches said:
I don't like to give too much advise online as it can be misinterpreted,
Click to expand...

Or picked apart :)

But one must never assume an inverter will trip an RCD, a lot of stuff coming out of factories are not wired to do so.
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Indeed, I'm currently rewiring a 55ft classic motor yacht that is fitted with an inverter which has no such RCD protection.
 
When people have sat exams and done years of training, then qualify as an industrial electrician..... I'm happy to have sensible discussions with people over forums.

Forums are dangerous. Everyone is the best electrician, wood bother, sail maker, polisher, engineer, etc until something goes wrong and someone gets hurt or dies.... then questions are asked. No paperwork = severe issues for both the installer and their insurer. Installation certificate with essential tests by a qualified person solves a lot of questions in an inquest. Same as gas really.

For someone to suggest "he is fairly sure regs would go pear-shaped" doesn't fill me with confidence..... First of all... what regs are we working to? Why can't you have 2 phases in 1 enclosure? How do 3 phase systems work? How does DNO distro gear function if you can't have more than 1 phase in a cabinet :sleeping: :sleeping: :sleeping:

Just today I had my hand in a workshop sub panel, all 3 phases live and less than 20mm from each other.


I digress....

Inverter needs checking. 3 types are manufactured. Good, bad and shite.


PaulRainbow said:
Or picked apart :)



Indeed, I'm currently rewiring a 55ft classic motor yacht that is fitted with an inverter which has no such RCD protection.
Click to expand...
 
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matthewriches said:
When people have sat exams and done years of training, then qualify as an industrial electrician..... I'm happy to have sensible discussions with people over forums.

Forums are dangerous. Everyone is the best electrician, wood bother, sail maker, polisher, engineer, etc until something goes wrong and someone gets hurt or dies.... then questions are asked. No paperwork = severe issues for both the installer and their insurer. Installation certificate with essential tests by a qualified person solves a lot of questions in an inquest. Same as gas really.

For someone to suggest "he is fairly sure regs would go pear-shaped" doesn't fill me with confidence..... First of all... what regs are we working to? Why can't you have 2 phases in 1 enclosure? How do 3 phase systems work? How does DNO distro gear function if you can't have more than 1 phase in a cabinet :sleeping: :sleeping: :sleeping:

Just today I had my hand in a workshop sub panel, all 3 phases live and less than 20mm from each other.


I digress....

Inverter needs checking. 3 types are manufactured. Good, bad and shite.
Click to expand...

No idea which of that was aimed in my direction, but i'm perfectly capable of checking the inverter, it's how i know it doesn't have RCD protection.
 
I've always liked the simplicity of plugging the output of the Invertor into the 240V input socket... so you can't have 240V mains and inverted feeding at once.

But you probably then would want to find a way to switch the charger and invertor so you can't try charging off the invertor...
 
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