Is an RCD needed in a MH

[Drummerboy]

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

FYI
"If it detects electricity flowing down an unintentional path, such as via a person or faulty appliance down to earth, then the RCD will switch off the circuit very quickly, reducing the risk or death, injury or fire. Device monitors the ingoing and outgoing current flow and trips when an imbalance occurs."
Have one fitted by a qualified electrician .

 

[dunnah01]

you have an 8a electric shower? Gosh. I bet sites love you

Truma Combi is up to 1800w so about 7.5amp to heat water + fans for gas if used at the same time so 8 amps sounds about right.

 

[xsparks]

I've never seen a Motorhome consumer unit wired like that, they are normally just wires connecting them.

My consumer unit appears to be no different from a domestic unit. An rcd mains unit, common bus bar and 10a breakers. I have installed an amp meter in the feed so I know exactly what each item is drawing. Giving you the opportunity to check your load given that sometimes you only have a 6a supply.

 

[Lenny HB]

My consumer unit appears to be no different from a domestic unit. An rcd mains unit, common bus bar and 10a breakers. I have installed an amp meter in the feed so I know exactly what each item is drawing. Giving you the opportunity to check your load given that sometimes you only have a 6a supply.

Perhaps it's different in some vans I've only looked at German vans.

 

[autorouter]

you have an 8a electric shower? Gosh. I bet sites love you

Standard Truma heater/water heater with 2 x 900W mains elements as an option.

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[DavidCh]

My apologies

 

[autorouter]

My consumer unit appears to be no different from a domestic unit. An rcd mains unit, common bus bar and 10a breakers.

Standard UK domestic consumer units are not a good idea in motorhomes. All the breakers are single-pole, on the live supply. Since about 2008 it's been recommended that motorhomes have double-pole breakers and a double-pole RCD. EHU posts must have an RCD and double-pole MCB, but I have the impression that it's not actually a regulation that motorhomes and caravans need to have them.

Double-pole MCBs are difficult to find in the average DIY store, you have to go to specialist suppliers like CEF to get them. Most RCDs are double-pole fortunately, but if you try really hard you can find single-pole RCDs.

 

[funflair]

What on earth would you be running in a MH to get to 16A?

Alde heating is 3kw flat out so add 2kw for a kettle and that’s best part of 20A with two items, that’s why Alde offer the load monitor so it can shut down temporarily while the kettle boils.

 

[xsparks]

I appreciate that all vans are fitted with different kit but as a guide these a my current draws.
Onboard charger. 0.058a
Fridge Dometic Rm7360 0.49a
Water Heater 3.8a
Heating 2KW 8.3a
1KW 4.2a
500W 2.2a
Hope this is useful.

 

[dunnah01]

Flippin 'eck - mines an Type AC RCD in the van - do I need a Type A?

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[CazPaul]

Although I've order the new van in the UK I've specced Continental sockets, much more useable in a van.

How do you mean much more useable?

Ours is a German registered van with all original sockets, we just use the adapters.

 

[Lenny HB]

How do you mean much more useable?

Ours is a German registered van with all original sockets, we just use the adapters.

When they fit UK sockets often they are awkward to use in the postions they fit then, continental sockets much easier as the plugs are neater & round and you can plug then in either way round.

 

[autorouter]

Flippin 'eck - mines an Type AC RCD in the van - do I need a Type A?

Type AC is 'General Purpose', for standard AC mains circuits. Type A is the same as Type AC, plus it will protect against some 'DC' faults that might happen in a charger or inverter, for example. In theory I suppose you should change it to Type A, but I don't think it's an urgent problem.

 

[DavidCh]

Type AC is 'General Purpose', for standard AC mains circuits. Type A is the same as Type AC, plus it will protect against some 'DC' faults that might happen in a charger or inverter, for example. In theory I suppose you should change it to Type A, but I don't think it's an urgent problem.

Please correct me where I am wrong but my understanding is that type A is to handle a potential DC voltage that could kill you which means over 50v. Designed to cope with issues on EV chargers that have very high DC voltages that could in a fault situation put these on the AC circuits. There is also a risk with inverter systems based around 48v and higher batteries for the same reason (a 48v battery could go to 55v, taking it over the 50v figure). As we would never have more than 12v in a Motorhome (maybe 24v) they are not required?

 

[autorouter]

Please correct me where I am wrong but my understanding is that type A is to handle a potential DC voltage that could kill you which means over 50v. Designed to cope with issues on EV chargers that have very high DC voltages that could in a fault situation put these on the AC circuits. There is also a risk with inverter systems based around 48v and higher batteries for the same reason (a 48v battery could go to 55v, taking it over the 50v figure). As we would never have more than 12v in a Motorhome (maybe 24v) they are not required?

The RCDs for EV chargers are Type B. Type A are for possible faults with electronic stuff like mains chargers. The old transformer devices stepped the voltage down immediately to about 20V AC, but the more modern 'switch mode' devices work directly on the incoming mains wave, turning it into DC, chopping it and feeding it into big capacitors. If that goes wrong, there's a possibility of high voltage pulsating DC getting out, and this wouldn't be detected by Type AC. As I said, I don't think it's an urgent problem, but if you are buying new you might as well buy the right type.

Selection of RCD Types - Hager UK

RCD's exist in various different forms and react differently depending on the presence of DC components or different frequencies.

hager.com

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[DavidCh]

I love this site Thank you

 

[treblid]

more modern 'switch mode' devices work directly on the incoming mains wave, turning it into DC, chopping it and feeding it into big capacitors. If that goes wrong, there's a possibility of high voltage pulsating DC getting out, and this wouldn't be detected by Type AC.

The key issue with original RCDs before these types became available was that a DC fault (leakage current) would polarise the RCD detection windings and stop it working on AC as well as DC faults.

I know this because I was the one that brought the issue to MK when we were evaluating protective systems for new 'half mains' TV chassis servicing.

 

[DavidG58]

Thought I had best report back , it’s taken a while to get our electrician back to do the job , but done today