Lon nan Gruagach
Well-Known Member
Test:
On shore power make sure everything is off (preferably unplugged)
Turn on air con: if RCD trips get electrician to air con. also check earthing arrangement for generator power.
Air con works on generator but not on shore power??
- Thread starter Lon nan Gruagach
- Start date
Test:
On shore power make sure everything is off (preferably unplugged)
Turn on air con: if RCD trips get electrician to air con. also check earthing arrangement for generator power.
IDAMAY
Well-Known Member
It could be that the aircon start up spikes the shore power if that gives only 16 amps whilst your generator produces quite a bit more. This will be particularly the case if it is an older aircon that needs a lot of power to start up. You could try just starting one unit at a time if you have multiple air handlers.
PEJ
Well-Known Member
Has anyone ever had this problem or know the solution?
I have two shore power cables one for sockets, water heater, etc and one just for the air con. The sockets are all ok on shore power but as soon as I plug the air con one in the rcd trips.
So I put the generator on and both sockets and air con work fine under generator power.
I have swapped the cables over and it makes no difference, so the problem is not the cable.
Any thoughts on what it could be?
I have two shore power cables one for sockets, water heater, etc and one just for the air con. The sockets are all ok on shore power but as soon as I plug the air con one in the rcd trips.
So I put the generator on and both sockets and air con work fine under generator power.
I have swapped the cables over and it makes no difference, so the problem is not the cable.
Any thoughts on what it could be?
Lon nan Gruagach
Well-Known Member
Test:
On shore power make sure everything is off (preferably unplugged)
Turn on air con: if RCD trips get electrician to air con. also check earthing/ neutral earth tie arrangement for generator power.
Mr Googler
Well-Known Member
I’ve had the exact same issue.
With much help from superheat6k, I changed the capacitors and tried a soft start to no avail.
The solution is simple, and is what superheat6k said at the start......you need a motor rated trip at the pontoon source.
Have a look as chances are you have a B rated trip at the pontoon supply.. Good for normal sockets but can’t handle the spike when the compressor cuts in. You need a C rated. My marina pt one in no problem.
Start capacitors do degrade so that won’t help. I changed mine and the spike defo reduced. Make sure you know what your doing though. They hold some wallop even when disconnected.
With much help from superheat6k, I changed the capacitors and tried a soft start to no avail.
The solution is simple, and is what superheat6k said at the start......you need a motor rated trip at the pontoon source.
Have a look as chances are you have a B rated trip at the pontoon supply.. Good for normal sockets but can’t handle the spike when the compressor cuts in. You need a C rated. My marina pt one in no problem.
Start capacitors do degrade so that won’t help. I changed mine and the spike defo reduced. Make sure you know what your doing though. They hold some wallop even when disconnected.
Lon nan Gruagach
Well-Known Member
If that is the fix (and its a valid thought), then its not an RCD thats tripping.. its a MCB.
PEJ
Well-Known Member
Yeah, tried that but even with the air con switched off as soon as the shore power cable was connected the trip switch tripped. I don't know my RCDs from my MCBs but the thing that trips is the main first thing on the boat in the lazzerette next to the trip for shore line one (which is fine).
PEJ
Well-Known Member
Hmmmm.....
I wondered about that too but it has been plugged in to that socket for the last 6 months without any problems it is only this visit that the problem has surfaced. I wonder if the marina changed the trip while I was away? but even if they did, see above, it is not the power demand from the air con that trips it, it trips as soon the cable is put in.
PEJ
Well-Known Member
Portofino
Well-Known Member
Mr Googler
Well-Known Member
I looked up the Eaton website. c rated combined rcd/mcb.
If it’s tripping as soon as you put the socket in, got a short somewhere. I would check the socket that’s tripping first for water or the wiring behind the socket. If it runs off the genie ok, must be an issue between the shore power socket affected and the trip I would have thought.
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Lon nan Gruagach
Well-Known Member
So, air con unplugged all works fine from shore power. Plug in air cone (even with it switched of) and everything goes pear shaped:
OK, so the air con works from genny but...
Definitely get sparky to look at air con, and I strongly suspect that the genny does not have Earth to Neutral tie (or mebby you dont have RCD on boat?)
septiclecky
Well-Known Member
C type 32amp combined RCD/MCB with a RCD trip current 30mA
D
Deleted User YDKXO
Guest
Sorry but maybe youve done this already but have you tried plugging the cable into a different shorepower socket? Thats going to tell you straightaway whether its the boat or the socket. Have you checked inside the plugs at either end of your cable? Plugs can corrode inside and short out or a wire could be loose inside. Both have happened to me in the past
Lon nan Gruagach
Well-Known Member
PEJ
Well-Known Member
Yes, tried all that, even put my neighbour's cable in my boat and my cable in his boat and so I am pretty sure the cables are ok.
I think I will have to take Dougal's advice and get a sparky to have look.
jrudge
Well-Known Member
You should be able to isolate this with a bit of effort ( better than paying the electrician !)
The ac will probably have a number of parts. Compressor units, Feed pump and numerous air handlers.
One of these has a fault.
The boat either has no rcd for the generator or he threshold at which it trips is higher than the shore box.
To find the faulty part you have to disconnect ( not just turn off ) both the live and neutral for each in turn. Turn on shore power and eventually it won’t trip and you have found the unit.
These should all be fed from your distribution switchboard so hopefully most of the effort will be in one place.
The feed pump is probably a nice place to start as it has salt water in it !
Assume you are in Cala dor at the moment ?
The ac will probably have a number of parts. Compressor units, Feed pump and numerous air handlers.
One of these has a fault.
The boat either has no rcd for the generator or he threshold at which it trips is higher than the shore box.
To find the faulty part you have to disconnect ( not just turn off ) both the live and neutral for each in turn. Turn on shore power and eventually it won’t trip and you have found the unit.
These should all be fed from your distribution switchboard so hopefully most of the effort will be in one place.
The feed pump is probably a nice place to start as it has salt water in it !
Assume you are in Cala dor at the moment ?
Portofino
Well-Known Member
Trips before the Aircon is switched on .
So all those components see no A/C
As said there’s damp or some other poor short circuit in the actual socket on the boat .See my post ^^^
3 shore power leads do the same thing , And his 2 x leads work fine on the neighbour s
The socket needs pulling and checking - loose wire shorting or as said 8iss wet .
Presume with the geny on the 3 way switch is such this dodgy socket is off ,so the geny on side does not see this fault - hence does not trip .
Pic —- nice to have a pic / location of this 2nd dedicated - shoe power air-con only “IN “ socket
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superheat6k
Well-Known Member
Interesting one.
Can I be clear what I have read - when you plug in the AC power lead the RCD / MCB trips immediately ?
Thanks to Farsco, but in this case the trip is C Rated 32 amps, so should be just fine. It is a combined RCD / MCB (I also googled the Eaton type number) so could be an earth leakage issue or a current overload. As it trips can you hear a popping sound, or just a click ? Popping suggests current is flowing, whereas a click is the RCD detecting ~ 30mA leakage current.
Does it trip with the AC turned off when the shore power is plugged in ?
This looks like an earth leakage problem, i.e. some of the current flowing is finding its way back to the source via the earth feeder. It sound like the generator connection is not using the on board RCD, which is not ideal and this should be checked and corrected.
Now a left field question ...
You mention a separate shore power lead. Are these supplies in any way connected on the boat ? My thoughts are that if they are the power from one supply could be routing out via the other, or even worse the two could be picking up different phases. This is possible if plugged into different posts being fed form different phases of the source supply.
If you can't solve this one easily please get a professional involved. The voltage between two adjacent phases is 415, and this is seriously lethal.
Can I be clear what I have read - when you plug in the AC power lead the RCD / MCB trips immediately ?
Thanks to Farsco, but in this case the trip is C Rated 32 amps, so should be just fine. It is a combined RCD / MCB (I also googled the Eaton type number) so could be an earth leakage issue or a current overload. As it trips can you hear a popping sound, or just a click ? Popping suggests current is flowing, whereas a click is the RCD detecting ~ 30mA leakage current.
Does it trip with the AC turned off when the shore power is plugged in ?
This looks like an earth leakage problem, i.e. some of the current flowing is finding its way back to the source via the earth feeder. It sound like the generator connection is not using the on board RCD, which is not ideal and this should be checked and corrected.
Now a left field question ...
You mention a separate shore power lead. Are these supplies in any way connected on the boat ? My thoughts are that if they are the power from one supply could be routing out via the other, or even worse the two could be picking up different phases. This is possible if plugged into different posts being fed form different phases of the source supply.
If you can't solve this one easily please get a professional involved. The voltage between two adjacent phases is 415, and this is seriously lethal.
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steadyeddy
Well-Known Member
Sounds like a in rush current problem as others have said up rate the trip rating.