Is an RCD needed in a MH

activecampers said:
Odd - (a) thats missing, and (b) that will allow you to draw 23A from the hookup - yet the cable and socket is rated to 16A only regardless of what the supply could give. So you could max the 23A through an unrestricted EHU post and overload cable, socket and get into a right mess.

There is a reason the one I posted above has 10+6!
Click to expand...
The MCBs don't have to add up to 16A. Depending on the way you split up the circuits, you could have for example five 10A MCBs on a 16A supply. The EHU supply won't be unrestricted, it will be coming in via a 16A plug and socket, so it will have a 16A MCB maximum. It's up to the user to switch the appliances so that the EHU doesn't trip.

If you are bothered about tripping the EHU post, you could add a 16A MCB before all your other MCBs, and hope that it trips before the EHU post.

All motorhomes need an RCD. It's basic shock protection. Usually it's easy to add one, the only possible problem is you might need the next size of box to mount them in. Or get a small box separately, like is used for a shower or a garage. Looking at the pic of the OP's box in post #10 it would be very easy to add an RCD.

If you really don't want to modify the box, it's possible to swap each MCB for an RCBO, which is a combined RCD and MCB. Quite often found nowadays in EHU posts.
 
Have just accidentally discovered an rcd in a locker close to the hook up entry in my Hymer, the clear panel still has the protective film applied when new seven years ago.
 
Last edited:
DavidG58 said:
I plugged a garden chipper into a socket in MH and tripped the MCB 🤔 works fine on house sockets 🤔
Click to expand...
Household sockets are on a 32amp ring circuit.
Motorhome sockets will be on a 10amp radial.

Radial is each socket is wired to the previous socket....the first one going the the breaker.
 
autorouter said:
The MCBs don't have to add up to 16A. Depending on the way you split up the circuits, you could have for example five 10A MCBs on a 16A supply. The EHU supply won't be unrestricted, it will be coming in via a 16A plug and socket, so it will have a 16A MCB maximum. It's up to the user to switch the appliances so that the EHU doesn't trip.

If you are bothered about tripping the EHU post, you could add a 16A MCB before all your other MCBs, and hope that it trips before the EHU post.

All motorhomes need an RCD. It's basic shock protection. Usually it's easy to add one, the only possible problem is you might need the next size of box to mount them in. Or get a small box separately, like is used for a shower or a garage. Looking aYou t the pic of the OP's box in post #10 it would be very easy to add an RCD.

If you really don't want to modify the box, it's possible to swap each MCB for an RCBO, which is a combined RCD and MCB. Quite often found nowadays in EHU posts.
Click to expand...
Thats assuming the hookup is fused or protected by an MCB. 16A plugs & sockets are not fused. Assuming it has a working MCB of 16A or less on the post is dangerous, outside of the UK at least. I've certainly used unrestricted ones in far slung places!

We are, of course, talking theoretically, but my point being, best practice you need to ensure YOU are in control and can protect your gear regardless of what you are plugged into. Having the theoretical ABILITY to draw >16A passes that control to someone else.
 
pappajohn said:
Household sockets are on a 32amp ring circuit.
Motorhome sockets will be on a 10amp radial.

Radial is each socket is wired to the previous socket....the first one going the the breaker.
Click to expand...
Not all sockets are on 32A ring, radial wiring also legit in households as are lower powered fused spurs. Main point being, using a 13A UK plug will be fused at 13A max so would blow well before the household MCB which renders all this irrellevent. A home grade garden shredder is going to be 13a max

Subscribers  do not see these advertisements

 
Last edited:
activecampers said:
Not all sockets are on 32A ring, radial wiring also legit in households. Main point being, using a 13A UK plug will be fused at 13A max so would blow well before the household MCB
Click to expand...
Only if you are using 13 amp sockets & plug tops, none in my van. :rofl:
 
activecampers said:
Thats assuming the hookup is fused or protected by an MCB. 16A plugs & sockets are not fused. Assuming it has a working MCB of 16A or less on the post is dangerous, outside of the UK at least. I've certainly used unrestricted ones in far slung places!
Click to expand...
None of the domestic plugs in Europe are fused. They use double pole breakers in the consumer unit. The round blue 16A plugs and sockets are standard throughout Europe, and are not fused. They have proper double-pole MCB protection, and an RCD as well. In the UK that's also true for the round blue plugs and sockets.

The only place you find fused plugs is in the UK, which has 32A ring mains for sockets so still needs a fuse in the appliance plug.

Subscribers  do not see these advertisements

 
Our 2005 Frankia has a factory fitted RCD. I'm amazed that they weren't compulsory many years ago. In my opinion they're more essential in a motorhome or caravan than at home (we've had an RCD at home since the 1980s).
 
activecampers said:
Thats assuming the hookup is fused or protected by an MCB.
Click to expand...
Don't get many of those in Morocco.....

Screenshot_20230215-224504-000.png
 
Lenny HB said:
Hymer and other German manufacturers never used to fit them, our first Hymer we bought new in 2008 didn't have one, I fitted one.
Yes it is well worth fitting one for the few bob they cost.
Click to expand...
Just sold my 2012 built Hymer, that had one, I know because it failed, unusual I know but it did, luckily I was in Taunton and VanBitz replaced it for me.
 
autorouter said:
If you are bothered about tripping the EHU post, you could add a 16A MCB before all your other MCBs, and hope that it trips before the EHU post.
Click to expand...
Good idea in theory but not going to help much on a 3 amp outlet and most sites are 6 amp or 10 amp anyway.

Subscribers  do not see these advertisements

 
DavidG58 said:
Our Hymer has never had one, not sure if ever fitted or removed by dealer or previous owner

It hasn’t crossed my mind to fit one or even worry about not having one, based on all U.K. supplies we will connect to will have an RCD, or am I wrong to think that as well 🤔

Only raised as query now as daughter is having a van converted and she asked me if we had one, her convertor asked her if she wanted one and she has said yes
Click to expand...
Without one fitted. and an electrical fault occurs you could get the whole vehicle live and you may only find out when you try to leave the van or somebody out side touches the van, with an RCD fitted you should live to tell the tail.
 
I would never rely on someone else's equipment to protect me when I can have my own as a backup.
 
Putting a 16a breaker before the others is not as simple as implied as all the breakers are fed by a common bar fed from the mains isolate. I'm sure there will be people that disagree but you only need to read some of the posts to appreciate the capabilities of some.
 
xsparks said:
Putting a 16a breaker before the others is not as simple as implied as all the breakers are fed by a common bar fed from the mains isolate. I'm sure there will be people that disagree but you only need to read some of the posts to appreciate the capabilities of some.
Click to expand...
Two common bars, live and neutral, I hope, because the MCBs should be double-pole. There should be an RCD in between the isolater and the MCBs anyway, unless there is only one RCD and it's used as an isolater. You'd just have to use bits of wire instead of the nice neat busbars all the way across.
 
This seems a pointless exercise since you will often be offered less than a 16a supply. And who's to say your breaker will trip before the site supply. It makes more sense to be aware of individual current draw from items and monitor your use.

Subscribers  do not see these advertisements

 
xsparks said:
This seems a pointless exercise since you will often be offered less than a 16a supply. And who's to say your breaker will trip before the site supply. It makes more sense to be aware of individual current draw from items and monitor your use.
Click to expand...
I agree, I was replying to someone who was concerned that an 'unrestricted' EHU supply could overload the cable if the MCBs added up to more than 16A total. I said it's very rarely a problem but if he was concerned he could fit a 16A MCB on the incoming supply.
 
What on earth would you be running in a MH to get to 16A?
 
DavidCh said:
What on earth would you be running in a MH to get to 16A?
Click to expand...
When you get back from your long walk, and put the kettle on (4A), turn the fan heater on (2A) turn on the water heater for a shower (8A), then put your Fray Bentos pie in the microwave (5A).
 
you have an 8a electric shower? Gosh. I bet sites love you :)
 
xsparks said:
Putting a 16a breaker before the others is not as simple as implied as all the breakers are fed by a common bar fed from the mains isolate. I'm sure there will be people that disagree but you only need to read some of the posts to appreciate the capabilities of some.
Click to expand...
I've never seen a Motorhome consumer unit wired like that, they are normally just wires connecting them.

Subscribers  do not see these advertisements

 

Join us or log in to post a reply.

To join in you must be a member of MotorhomeFun

Join MotorhomeFun

Join us, it quick and easy!

Join us

Log in

Already a member? Log in here.

Latest journal entries

Back
Top