Help req'd to find a plug for this socket

[VicS]

What is a 63 volt rcd?

A misprint, or misunderstanding

Cygnusv almost certainly meant 63A ... which is a typical maximum current rating for such devices.
It is not related to the residual current value which will cause the device to trip ... that is usually 30mA
Nor is it an over load current which will cause it to trip. RCDs do not have an overload trip function.

It is merely the maximum current carrying capacity rating of the device. They are available in range of current ratings.

 

[[163233]]

Portable generators, that cannot have their neutral and Earth connections bonded are what they say on the tin, portable. There is nothing wrong with using them as portable units, but they should not be used as fixed installations. They should not be plugged into the boats AC shore power inlet.

Boats are portable though...

 

[Stemar]

All AC power sources, whether it be mains, generator or inverter, when connected to the vessels input socket, should have the neutral and ground bonded at source. Never mind "according to you", it's common sense, good practice and would be forbidden by current build regs.

Maybe things have changed, but when I lived in France, the neutral wasn't necessarily at earth potential. I had a job repairing vending machines and was trying to find a fault, so I measured 220v between L & N, something like 400v between L & E and 180v between N & E. I went to see the maintenance manager to warn him about the fault and he explained why it wasn't a fault. It was an electronics factory, belonging to a big manufacturer of everything from TVs to toasters, so he probably had a rough idea how things were supposed to work.

 

[rogerthebodger]

Maybe things have changed, but when I lived in France, the neutral wasn't necessarily at earth potential. I had a job repairing vending machines and was trying to find a fault, so I measured 220v between L & N, something like 400v between L & E and 180v between N & E. I went to see the maintenance manager to warn him about the fault and he explained why it wasn't a fault. It was an electronics factory, belonging to a big manufacturer of everything from TVs to toasters, so he probably had a rough idea how things were supposed to work.

Different countries have different setups.

As you found the French system is a floating system. Floating systems normally need double pole switching.

The UK and South Africa have the neutral earth connection at the supply substation or supply generator.

As there is an alternate path for the electricity to return to the neutral via the earth / earth connection, a RCD can detect any difference in the current in the live and neutral supply lines.

This will give you some idea of the different systems

Earthing system - Wikipedia

 

[Graham376]

Portable generators, that cannot have their neutral and Earth connections bonded are what they say on the tin, portable. There is nothing wrong with using them as portable units, but they should not be used as fixed installations. They should not be plugged into the boats AC shore power inlet.

All AC power sources, whether it be mains, generator or inverter, when connected to the vessels input socket, should have the neutral and ground bonded at source. Never mind "according to you", it's common sense, good practice and would be forbidden by current build regs.

I'm not talking about a permanent installation. With an isolated mains circuit on the boat, plugging a portable generator into the shore power socket to use the battery charger or microwave is in reality no different to using the boat circuit as a multi socket extension lead from the generator, the feed from which goes through the rcd and breakers.

 

[rogerthebodger]

I'm not talking about a permanent installation. With an isolated mains circuit on the boat, plugging a portable generator into the shore power socket to use the battery charger or microwave is in reality no different to using the boat circuit as a multi socket extension lead from the generator, the feed from which goes through the rcd and breakers.

The point is that without a neutral /earth link at the generator then RCD will not work as there will be no alternate path to the neutral.

The other argument is that as there is no earth path back to the neutral you would not get a shock in theory but in practice is a different matter.

 

[Sandyman]

I'm not talking about a permanent installation. With an isolated mains circuit on the boat, plugging a portable generator into the shore power socket to use the battery charger or microwave is in reality no different to using the boat circuit as a multi socket extension lead from the generator, the feed from which goes through the rcd and breakers.

Quite agree Graham376. Makes no difference whatsoever. As to being forbidden by building regs..................well. I live onboard in the real world & couldn't give a monkeys left knacker-sack to building regs.

 

[Graham376]

The point is that without a neutral /earth link at the generator then RCD will not work as there will be no alternate path to the neutral.

The other argument is that as there is no earth path back to the neutral you would not get a shock in theory but in practice is a different matter.

The RCD test button worked when I tested some time ago but even if it doesn't work, that's no different to someone plugging power tools directly into the generator which is the way most use them.

 

[rogerthebodger]

The RCD test button worked when I tested some time ago but even if it doesn't work, that's no different to someone plugging power tools directly into the generator which is the way most use them.

You are correct in that a power tool plugged directly in the generator will work. I did that and dropped my power tool in the sea. The generator did not trip and when I pulled the drill out of the sea I got a shock.

If I had had a RCD between the drill and the generator with the earth /neutral connected the RCD would have tripped. The generator did labour but the overload did not trip.

The test button on an RCD just bipasses one of the current detecion coils.

Of course you can use your generator as is your choice.

 

[LadyInBed]

I did that and dropped my power tool in the sea. The generator did not trip and when I pulled the drill out of the sea I got a shock.

I would have thought it prudent to stop the Gen before pulling what was a live cable out of the sea!

 

[rogerthebodger]

I would have thought it prudent to stop the Gen before pulling what was a live cable out of the sea!

Yes you are very correct I should have done but I didn't so I got a jolt

 

[andsarkit]

Unless I am missing something obvious the RCD will trip if the current going up the live differs from the current coming back on the neutral by more than 30mA. The missing 30mA is either a fault or you are touching the live and providing a path to earth. It doesn't matter if the circuit has a grounded neutral or it is floating at some arbitrary voltage because the RCD will still work. In order to electrocute yourself you would need to have insulating shoes and hold both the live and neutral wires which is rather unlikely.
Some early RCDs used to have an earth wire. I was never quite sure of the purpose but expect it would detect voltage on the neutral wire. In this case it would be essential to connect the neutral to ground at the generator and also ground the generator or you could find the earthed appliance cases having a voltage on them.
I have also found that the input filters on some electrical devices provide a capacitive path to ground and if you have several connected it can cause the RCD to trip. ( needs about 10 devices for this to happen)

 

[rogerthebodger]

Unless I am missing something obvious the RCD will trip if the current going up the live differs from the current coming back on the neutral by more than 30mA. The missing 30mA is either a fault or you are touching the live and providing a path to earth. It doesn't matter if the circuit has a grounded neutral or it is floating at some arbitrary voltage because the RCD will still work. In order to electrocute yourself you would need to have insulating shoes and hold both the live and neutral wires which is rather unlikely.
Some early RCDs used to have an earth wire. I was never quite sure of the purpose but expect it would detect voltage on the neutral wire. In this case it would be essential to connect the neutral to ground at the generator and also ground the generator or you could find the earthed appliance cases having a voltage on them.
I have also found that the input filters on some electrical devices provide a capacitive path to ground and if you have several connected it can cause the RCD to trip. ( needs about 10 devices for this to happen)

Any one who has any knowledge of physics will know of the conversation of energy in that energy cannot be created or destroyed.

So energy is volts x Amps x time.

At any oint in time and with a constant voltage. current musst be the same.

This is also defined in kirchoffs 2nd law.

So in a closed electrical the current flowing in the live in the live line must equal the current flowing in the neutral line.

You state If the current going up the live differs from the current coming back on the neutral by more than 30mA. The missing 30mA is either a fault
So in a fault condition where does the 30mA go or put it another way how does the 30mA difference in the live and neutral lines get back to the neutral at the generator.

The answer is in partially in your second point, " touching the live and providing a path to earth. " So now how does the 30mA in the eath gat back to the neutral at the generator.

The answer is through the connection between the earth and neutral at the generator.

The 30 mA is what had been found a safeish current that can pass through a human being without too much harm. Of there can be conditions where even this and be deadly.

If you don't have an RCD in circuit together with a neutral /earth connection , touching the live without an RCD AND a N/E link could cause current much more than 30mA to flow through you which could kill you.

I don't know if I can make it any simpler

This shows how the currents flaws through the earth /neutral connection of the secondary of the transformer on the left hand side

 

[penberth3]

Any one who has any knowledge of physics will know of the conversation of energy in that energy cannot be created or destroyed.......

You state If the current going up the live differs from the current coming back on the neutral by more than 30mA. The missing 30mA is either a fault
So in a fault condition where does the 30mA go or put it another way how does the 30mA difference in the live and neutral lines get back to the neutral at the generator.

andsarkit hasn't said anything wrong, so why the lecture?

Not a very good lecture either, at least two mistakes in your diagram.

 

[rogerthebodger]

andsarkit hasn't said anything wrong, so why the lecture?

Not a very good lecture either, at least two mistakes in your diagram.

Ok I won't make a lecturer.

I do find a lack of understanding of the details of how an RCD works.

The diagrams are not mine so if there are mistakes I would be grateful if you pointed then out to me so I can learn something.

I am always pleased to learn as I know I don't know everything.

Yes the earth leakage current is not 0.006A its 0.004A

 

[andsarkit]

I have to agree with you Roger. The bit I had missed is that without a grounded neutral the system is floating and so effectively the same as using an isolating transformer. The RCD will not trip but you will not get a shock either because the wire you touch will go to ground potential and the other wire will go to 230V.
As soon as you ground the neutral it is essential to have an RCD for protection.

 

[rogerthebodger]

I have to agree with you Roger. The bit I had missed is that without a grounded neutral the system is floating and so effectively the same as using an isolating transformer. The RCD will not trip but you will not get a shock either because the wire you touch will go to ground potential and the other wire will go to 230V.
As soon as you ground the neutral it is essential to have an RCD for protection.

I agree with you that a balanced system should not give you a shock.

One time I was using my Honda generator non inverter type I was stupid enough to drop a drill in the sea and fished it out without turning the generator off.

Theority I should no get a shock but I did so I an very careful and really don't wish others to be a silly as I was. I got away with it but the next person might not.