32amp shorepower supply - will it be OK?

[kcrane]

I'm pretty sure this question comes up often, but a search didn't give me quite the clarity I was hoping for.

We normally plug into a 16amp supply, using one of the smaller blue plugs (three round prongs, one larger than the others two and a notch on the socket to make sure it goes in right.)

We have occassionally drawn more than 16amps (two small heaters, then add a toaster and kettle) and it sometimes trips off at our panel on the boat rather than the marina trip switch on the pontoon. Presumably this shows our onboard electrics are designed to draw no more than 16amps.

Having said that we have a 7kw generator, which at 220v presumably can supply around 30amps?

We're moving to another marina for the summer and they've warned us the berth has a 32amp supply.

We have an adapter, which has the larger blue plug with a short cable attached to a blue 16amp socket.

Will it be OK to plug this adapter into the pontoon 32amp supply, then plug our normal 16amp lead into the trailing socket?

I assume we'd need to at least keep an eye on what we are drawing as the pontoon supply will not trip, but with the safety fallback that our own panel should trip if we draw too much?

If the type of supply was different (3 phase?) would the plugs be different colours?

 

[fireball]

Yes - it will be ok - it's always a good idea to keep an eye on the draw anyway. The fact that you seem to have a trip on your boat that goes at high load is good - if you know it does this under certain conditions it may be a good idea to test it with the 32amp connection to ensure it does trip as expected.

3 phase connectors have more pins - you can't connect a "normal" 32amp connector in to these - and I think they're red? well the ones I've seen are ...

 

[VicS]

The snag is that your shorepower cable, connectors and wiring from your inlet to the consumer unit (or MCB ) will only be protected by the 32 amp circuitbreaker on the pontoon.
In theory a fault (short) occurring anywhere on this lot could result in overheating of the 16 amp wiring before the 32 amp breaker on the pontoon trips.

If your cable and inlet wiring is 2.5mm² the risks are minimal

They are only 1.5 mm² the risks are greater.

Ideally you should have a 16 amp fuse in the 32amp to 16 amp adapter

 

[kcrane]

Ideally you should have a 16 amp fuse in the 32amp to 16 amp adapter

A good idea.

I have found a long (2009) debate amongst the Norfolk Broads fraternity that touches on the same idea but no-one seemed to know where you got an in-line weatherproof 220V 16amp fuse/circuit breaker.

http://www.the-norfolk-broads.co.uk/printthread.cfm?Forum=30&Topic=18431

 

[philip_stevens]

The best I can find are IP65 units.

But this could go inside one of these

 

[lustyd]

The best I can find are IP65 units.

But this could go inside one of these

Ip65 should be fine as it would cope with a hose being sprayed at it. As long as you put it somewhere it won't fall in the water it should be OK.

 

[VicS]

The best I can find are IP65 units.

But this could go inside one of these

Ah but

Thats just an RCD isn't it?

What is wanted is an MCB (or a fuse ) not an RCD.

I

 

[tcm]

I think the little adapter will get nicked. So i wd rewire to the bigger socket.

 

[Pinnacle]

I'm pretty sure this question comes up often, but a search didn't give me quite the clarity I was hoping for.

We normally plug into a 16amp supply, using one of the smaller blue plugs (three round prongs, one larger than the others two and a notch on the socket to make sure it goes in right.)

We have occassionally drawn more than 16amps (two small heaters, then add a toaster and kettle) and it sometimes trips off at our panel on the boat rather than the marina trip switch on the pontoon. Presumably this shows our onboard electrics are designed to draw no more than 16amps.

Having said that we have a 7kw generator, which at 220v presumably can supply around 30amps?

We're moving to another marina for the summer and they've warned us the berth has a 32amp supply.

We have an adapter, which has the larger blue plug with a short cable attached to a blue 16amp socket.

Will it be OK to plug this adapter into the pontoon 32amp supply, then plug our normal 16amp lead into the trailing socket?

I assume we'd need to at least keep an eye on what we are drawing as the pontoon supply will not trip, but with the safety fallback that our own panel should trip if we draw too much?

If the type of supply was different (3 phase?) would the plugs be different colours?

We have exactly the setup you describe. If we do draw too much, the main switch panel in the boat trips.

I may be tempting fate, tcm, but we havent had ours nicked in 3+ yrs......

 

[philip_stevens]

Ah but

Thats just an RCD isn't it?

What is wanted is an MCB (or a fuse ) not an RCD.

I

I thought it was, from the description on eBay.

From the description of it, it is an RCD/16A breaker.

Could be wrong though

 

[VicS]

I thought it was, from the description on eBay.

From the description of it, it is an RCD/16A breaker.

Could be wrong though

I think that means that it is an RCD with a max current rating of 16 amps. I dont beleive it incorporates any form of overload protection ... that would make it an RCBO.

 

[jimmy_the_builder]

Hi K

I'd be v surprised if your V48 was designed around a supply as small as 16A; when you say the panel trips - what actually trips out - the breaker protecting the sockets circuit on your board, or the main breaker, or the inlet protection breaker next to the shorepower inlet?

At a guess I'd expect you are overloading the individual circuit, rather than the installation as a whole. I'd guess that you have a 32A marinco inlet, probably protected at the inlet by a 30A breaker or thereabouts. I think you'll be able to swap your 16A commando plug for a 32A without issues. Incidentally these plugs are just a few quid from screwfix; they are what we use in La Rague.

Tell you what, as a special favour, I'll have a look at your installation tomorrow night!

Cheers
Jimmy

 

[philip_stevens]

I think that means that it is an RCD with a max current rating of 16 amps. I dont beleive it incorporates any form of overload protection ... that would make it an RCBO.

I see that now Vic.
I think the only way the OP is going to get an in-line RCBO is to make it up himself using an IP65 or 66 box - like shown, but without the connecting plugs i.e hard wired in, with a waterproof connection cover over the plug/socket.

 

[VicS]

I see that now Vic.
I think the only way the OP is going to get an in-line RCBO is to make it up himself using an IP65 or 66 box - like shown, but without the connecting plugs i.e hard wired in, with a waterproof connection cover over the plug/socket.

The RCD is probably not necessary. The pontoon RCD will still be effective ( hopefully in working order ) A (double pole??) MCB is all that is required.

But are the risks high enough to worry about them, esp if the shorepower cable is 2.5mm².
OTH is it possible that a very safety conscious marina would say no to plugging a 16amp lead and system into a 32 amp supply ?

In view of the fact that the OP already exceeds 16 amps on occasions and trips his own breaker I suppose the best advice would be for him to upgrade his installation to 32 amps.

 

[philip_stevens]

The RCD is probably not necessary. The pontoon RCD will still be effective ( hopefully in working order ) A (double pole??) MCB is all that is required.

But are the risks high enough to worry about them, esp if the shorepower cable is 2.5mm².
OTH is it possible that a very safety conscious marina would say no to plugging a 16amp lead and system into a 32 amp supply ?

In view of the fact that the OP already exceeds 16 amps on occasions and trips his own breaker I suppose the best advice would be for him to upgrade his installation to 32 amps.

Fully agree. A more than sensible suggestion - especially on electrical safety.

 

[kcrane]

Hi K

I'd be v surprised if your V48 was designed around a supply as small as 16A; when you say the panel trips - what actually trips out - the breaker protecting the sockets circuit on your board, or the main breaker, or the inlet protection breaker next to the shorepower inlet?

At a guess I'd expect you are overloading the individual circuit, rather than the installation as a whole. I'd guess that you have a 32A marinco inlet, probably protected at the inlet by a 30A breaker or thereabouts. I think you'll be able to swap your 16A commando plug for a 32A without issues. Incidentally these plugs are just a few quid from screwfix; they are what we use in La Rague.

Tell you what, as a special favour, I'll have a look at your installation tomorrow night!

Cheers
Jimmy

Well worked out.

When I stop and think it is the 'sockets' MCB that clicks off, not the whole shore power circuit.

I looked at socket where the shore power plugs into the boat and it is indeed a large Marinco socket. I think there is a clue in the fact that written on it in large font is '32amp'.

The shore power lead itself is also fairly heavy weight, so many apologies, I have led you all a merry dance, all I needed to do was a bit of investigating in advance.

Upside is I now know more about electrics!