electric breaker voltage

[petelee]

hi

hope someone can help.On our first outing in a caravan we kept tripping the rcd breaker in our van first with an ordinary household microwave and then with a kettle we decided to go and buy proper caravan equipment but my father in law has decided to upgrade the caravan main breaker up to 16amp from 10 and we're worried that all the wiring might melt or we'll keep blowing the site supply is there anything wrong with upgrading as in my experience the manufacturers normally put things like this in for a good reason

cheers

p.s please hurry as he's ordered the other breaker already

 

[rayc]

Peter, Is the RCD tripping or 10A MCB (fuse)? Most domestic type kettles draw approx 10amps( 3kw@240v) so your supply is borderline and as a kettle takes 2-3 minutes to boil then it will trip. If you already have other mains equipment switched on then it will trip sooner. The problem with micro waves is the start up current which can be several times the rated value.

Do not uprate the MCB or RCD but use low wattage items designed for caravans.

If you uprate to 16A then not only may you over load the circuit but unless the site supply is also 16A you may trip it.

 

[WatsonJohnG]

Very well put Ray

We had a posting about electric kettles recently and no need to buy a low wattage one was one reply

This shows every need.

We use a microwave but everything else is switched off first especially water heaters and space heaters.

Don't change the trip or you will be tripping to the site warden with cap in hand asking to be reconnected.Many sites are only 10 amp and 6 amp is not uncommon in France

Some commercial sites make a charge for this and most make you feel distinctly unpopular!!

 

[MikeP]

Peter, Is the RCD tripping or 10A MCB (fuse)? Most domestic type kettles draw approx 10amps( 3kw@240v) so your supply is borderline and as a kettle takes 2-3 minutes to boil then it will trip. If you already have other mains equipment switched on then it will trip sooner. The problem with micro waves is the start up current which can be several times the rated value.

Do not uprate the MCB or RCD but use low wattage items designed for caravans.

If you uprate to 16A then not only may you over load the circuit but unless the site supply is also 16A you may trip it.

3kw kettle is 12.5A at 240v or 13A at 230v. We use an old metal kettle on the hob - very rustic!

 

[gary]

You don't just have one mcb but two and combined they equal 16 amps, if you uprate to 16 amps on one the total will be 22 amps and without going into it...cause alsorts of problems.

If what Ray says about start up current is the problem then uprate the mcb to a 10amp 'C' grade rather that the 'B' fitted, these are designed to take a greater but shorter term overload.

 

[ProfJohnL]

3kw kettle is 12.5A at 240v or 13A at 230v. We use an old metal kettle on the hob - very rustic!

Hello Mike,

You have an interesting kettle! What you say is true, but not for the same kettle, The current used by a kettle is determined by the resistance of the element which doesn't change.

Given a kettle that consumes 3kw at 240V, the current would be 12.5 and the element resistance would be 19.2Ohms. Connect it to a 230V supply and the current would be 230/19.2 = 11.98A which gives a wattage of 2755.4 Watts.

The unified mains voltage now in the UK is supposed to be 230V ac, and all new appliances are rated at 230Vac.

so the same kettle would use 12.5 at 240Vac, but use it on 230Vac and the current wold drop to and the supply voltage.

 

[keith_5081818]

Well firstly i agree with most of the coments already made, i would not put in a bigger rcd, or replace the existing 10 amp mcb with a 16 amp one.

All new Baileys have a 15 amp and a 6 amp mcb, i was quite supprised they opted for 15 amp to be honest, ive been on sites where they only allowed 4 amps believe it or not.

But u should be tripping the mcb way before the rcd surely.

It is possible its faulty & is whats called nusance tripping, i.e a 25 milliamp rcd (which is what u should have in the van) is tripping at say 10 milliamps.

Now i'm not an electrician so i dont understand all the technical side, but when a van has a 16th edition electrical installation test done, ive seen a few fail because of it.

 

[ProfJohnL]

Hello Pete Lee,

Your question contains a number of inconstancies and I wonder if you have actually reported the problem accurately?

You state that the RCD (Residual Current Device)is tripping with either a Microwave or a domestic kettle. The RCD is a device that detects unsafe wiring or appliances - by comparing the amount of current flowing in the Live and neutral wires. Any difference indicates there is a current leakage and that is potentially dangerous and so it shuts of the power. The RCD does not respond to the power of the appliances and so it would not trip if you simply tried to draw too much current.

If the RCD is tripping then it indicates there is a fault with either the wiring or the appliance.

Over current is looked after by the MCB's (Miniature Current/Circuit Breakers). Assuming these were installed by the caravan manufacture, they will have been selected to match the wiring in the caravan, and and or relevant regulations. It is unsafe to replace an MCB with a higher rated unit, unless the wiring has also been checked and approved for that higher rating.

Your insurance company may refuse to honour any claim if you have a fault or claim relating to damage ensuing from or supported by a electrical source.

 

[MikeP]

Hello Mike,

You have an interesting kettle! What you say is true, but not for the same kettle, The current used by a kettle is determined by the resistance of the element which doesn't change.

Given a kettle that consumes 3kw at 240V, the current would be 12.5 and the element resistance would be 19.2Ohms. Connect it to a 230V supply and the current would be 230/19.2 = 11.98A which gives a wattage of 2755.4 Watts.

The unified mains voltage now in the UK is supposed to be 230V ac, and all new appliances are rated at 230Vac.

so the same kettle would use 12.5 at 240Vac, but use it on 230Vac and the current wold drop to and the supply voltage.

Thanks, I didn't know that.

 

[vauxhall2]

hi,sorry to jump on the band wagon but we are having the same problem on ours,bailey 500/5.i have ignored the problem because it only happens when all things are used,most times we switch off,sometimes forget.it happens when we are using the /battery charger,on all the time /water heater / kettle /electric heating /am i expecting too much of the trip box by overloading,or is there a fault?most sites we use are 16AMP.IT SAVES GOING FOR THE WARDEN THOUGH

 

[rayc]

I believe that some of the circuits are underated by the info being provided.

On my van (Compass 2000) everything is fed via a 40A 30ma RCD. There are then 3 MCB's: No 1 is a 10A class C and feeds the sockets / fridge / charger / lights. No 2 is 10A class C and feeds water heater only. No 3 is 6A class C which feeds the water heater only.

 

[PaulA3]

I back up John L very good explanation. you have to remember that 16amps is not a lot of current when you compare it to what is used at home for instance your sockets at home are run from a ring main with a fuse of 30amps. So you have to watch what your using in the van,take an ordinary 3kw kettle and apply OHMS law WATTS = AMPS X VOLTS so AMPS = WATTS dived by VOLTS.

thus 3000/240 = 12.5 amps, a Micro wave oven rated at 650 watts draws 1300 watts so 1300/240 = 5.4 amps so you see just having these 2 items on at the same time results in 17.9 amps result the MCB trips or the site MCB trips and you have to go find the warden.

The problem can be reduced by buying low wattage kettles microwave ect, but you do have to watch what you are using if like Micheal you have all the caravan appliances on battery charger,on all the time /water heater / kettle /electric heating and TV if they all add up to more than 3840 watts your in danger of triping out the site MCB.

Hope that helps Paul

 

[ProfJohnL]

I back up John L very good explanation. you have to remember that 16amps is not a lot of current when you compare it to what is used at home for instance your sockets at home are run from a ring main with a fuse of 30amps. So you have to watch what your using in the van,take an ordinary 3kw kettle and apply OHMS law WATTS = AMPS X VOLTS so AMPS = WATTS dived by VOLTS.

thus 3000/240 = 12.5 amps, a Micro wave oven rated at 650 watts draws 1300 watts so 1300/240 = 5.4 amps so you see just having these 2 items on at the same time results in 17.9 amps result the MCB trips or the site MCB trips and you have to go find the warden.

The problem can be reduced by buying low wattage kettles microwave ect, but you do have to watch what you are using if like Micheal you have all the caravan appliances on battery charger,on all the time /water heater / kettle /electric heating and TV if they all add up to more than 3840 watts your in danger of triping out the site MCB.

Hope that helps Paul

Thank you Paul for your support.

May I just correct one small thing in your added information:- The standards supply voltage in the UK is now harmonised with the rest of Europe at 230Vac, - so your worked examples will be slightly out.

 

[PaulA3]

Thank you Paul for your support.

May I just correct one small thing in your added information:- The standards supply voltage in the UK is now harmonised with the rest of Europe at 230Vac, - so your worked examples will be slightly out.

John you are quite right to correct me but it is work in progress and as can be seen here http://kropla.com/electric2.htm not yet achieved quote "Though nominal voltage has been officially changed to 230V, 240V is within tolerances and commonly found"

It is good you brought this up as 230 volts will in fact increase the current taken example the 3kwatt kettle now means 3000/230 = 13.04 AMPS makeing the situation even more critical reducing the watts on a 16amp 230Volts supply to 3680watts.

Paul

 

[PaulA3]

I back up John L very good explanation. you have to remember that 16amps is not a lot of current when you compare it to what is used at home for instance your sockets at home are run from a ring main with a fuse of 30amps. So you have to watch what your using in the van,take an ordinary 3kw kettle and apply OHMS law WATTS = AMPS X VOLTS so AMPS = WATTS dived by VOLTS.

thus 3000/240 = 12.5 amps, a Micro wave oven rated at 650 watts draws 1300 watts so 1300/240 = 5.4 amps so you see just having these 2 items on at the same time results in 17.9 amps result the MCB trips or the site MCB trips and you have to go find the warden.

The problem can be reduced by buying low wattage kettles microwave ect, but you do have to watch what you are using if like Micheal you have all the caravan appliances on battery charger,on all the time /water heater / kettle /electric heating and TV if they all add up to more than 3840 watts your in danger of triping out the site MCB.

Hope that helps Paul

John you are quite right to correct me but it is work in progress and as can be seen here http://kropla.com/electric2.htm not yet achieved quote "Though nominal voltage has been officially changed to 230V, 240V is within tolerances and commonly found"

It is good you brought this up as 230 volts will in fact increase the current taken example the 3kwatt kettle now means 3000/230 = 13.04 AMPS makeing the situation even more critical reducing the watts on a 16amp 230Volts supply to 3680watts.

Paul