Battery charger keeps tripping the main RCD in the house Swift challenger 580, 2010yr, powe supply EC 400

[fusilierphil]

Plugged the van Into the mains at home today as I was wanting to charge the Battery, seemed fine till I switched the charger on and mains in house tripped, tried a few times with same result, neither caravan RCD or MCB tripped

 

[RogerL]

At the risk of stating the perfectly obvious, there's a fault somewhere - the fact that the house tripped by the caravan didn't is down to the house having more sensitive equipment.

 

[Malx]

was it the RDD or MCB that tripped in the house?

 

[Woodentop]

If it didn't trip in the caravan then the fault must lie outside the protection zone of the caravan devices, i.e. something not in the caravan wiring or connected to it.

That leaves the incoming mains (plug) connector on the caravan, the EHU cable (both ends) or the power source into which the cable is plugged at the house end. That shouldn't be too difficult to find....

One thing to check - assuming that it was the RCD that tripped - is the leakage rating of both RCDs. They <should> both be 30mA and type B (which means that it will trip in 40mS or less for a 30mA leak.) If the domestic RCD is finer (i.e. such as 10mA leak) that would be why the house goes and not the caravan.

 

[ProfJohnL]

Assuming the title of teh thread is correct and it was the houses RCD that tripped, and the caravan one did not, it strongly points to teh EHU cable its self.

 

[fusilierphil]

If it didn't trip in the caravan then the fault must lie outside the protection zone of the caravan devices, i.e. something not in the caravan wiring or connected to it.

That leaves the incoming mains (plug) connector on the caravan, the EHU cable (both ends) or the power source into which the cable is plugged at the house end. That shouldn't be too difficult to find....

One thing to check - assuming that it was the RCD that tripped - is the leakage rating of both RCDs. They <should> both be 30mA and type B (which means that it will trip in 40mS or less for a 30mA leak.) If the domestic RCD is finer (i.e. such as 10mA leak) that would be why the house goes and not the caravan.

When the battery charger is turned off the power to the caravan is fine, it is only when the charger is turned on, checked the supply cable and that is ok, not yet checked both RCDs but will do, I have plugged a tester into the socket supplying the caravan and everything is ok, I am assuming it could be the charger but don't know enough about them to assume?

 

[fusilierphil]

was it the RDD or MCB that tripped in the house?

RCD

 

[Gralay]

RCD

Hi welcome to the forum
You could try boiling a domestic kettle full of water in the caravan with the charger preferably disconnected (if possible), if it boils without tripping the RCD the ehu ect is good then turn on the fridge and heating for a few minutes if still doesn't trip turn everything off and turn on /reconnect the charger (if you disconnect /reconnect the charger make the ehu is removed first) if it then trips it is probably the charger at fault.


Then you should also press the test button on the caravan RCD to ensure that it is working.

Gra

 

[fusilierphil]

Hi welcome to the forum
You could try boiling a domestic kettle full of water in the caravan with the charger preferably disconnected (if possible), if it boils without tripping the RCD the ehu ect is good then turn on the fridge and heating for a few minutes if still doesn't trip turn everything off and turn on /reconnect the charger (if you disconnect /reconnect the charger make the ehu is removed first) if it then trips it is probably the charger at fault.


Then you should also press the test button on the caravan RCD to ensure that it is working.

Gra

Hi Gra, thank you, I will certainly give your idea a try,

 

[Malx]

Sounds like charger has slight leakage current to Earth, all household electrical circuits will have a slight leakage. If the total leakage gets over 30mA the RCD trips.

Try turning off all household circuits bar one connect caravan to that.

Try connecting van to neighbours supply and see if it does the same?

I had single RCD in house for all circuits. It tripped occasionally, often in thunder. Got rid of old RCD and Swapped fuse box. New RCD tripped all the time. Swapped the fuse box for a replacement and it worked fine.

An electrician could measure your leakage current without the caravan plugged in and give some advice.

 

[fusilierphil]

Sounds like charger has slight leakage current to Earth, all household electrical circuits will have a slight leakage. If the total leakage gets over 30mA the RCD trips.

Try turning off all household circuits bar one connect caravan to that.

Try connecting van to neighbours supply and see if it does the same?

I had single RCD in house for all circuits. It tripped occasionally, often in thunder. Got rid of old RCD and Swapped fuse box. New RCD tripped all the time. Swapped the fuse box for a replacement and it worked fine.

An electrician could measure your leakage current without the caravan plugged in and give some advice.

Thanks for that🙂

 

[xtrailman]

Sounds like charger has slight leakage current to Earth, all household electrical circuits will have a slight leakage. If the total leakage gets over 30mA the RCD trips.

Try turning off all household circuits bar one connect caravan to that.

Try connecting van to neighbours supply and see if it does the same?

I had single RCD in house for all circuits. It tripped occasionally, often in thunder. Got rid of old RCD and Swapped fuse box. New RCD tripped all the time. Swapped the fuse box for a replacement and it worked fine.

An electrician could measure your leakage current without the caravan plugged in and give some advice.

I agree.

 

[Woodentop]

Sounds like charger has slight leakage current to Earth, all household electrical circuits will have a slight leakage. If the total leakage gets over 30mA the RCD trips.

Try turning off all household circuits bar one connect caravan to that.

Try connecting van to neighbours supply and see if it does the same?

I had single RCD in house for all circuits. It tripped occasionally, often in thunder. Got rid of old RCD and Swapped fuse box. New RCD tripped all the time. Swapped the fuse box for a replacement and it worked fine.

An electrician could measure your leakage current without the caravan plugged in and give some advice.

The comment above worries me. No item should have ANY leakage to earth, neither should the circuits assuming nothing connect to them. Given also that many items these days are double insulated and have only two core cable, how could that leakage to earth occur?
The only items that conceivably could have leakage are such as dishwashers, washing machines, and tumble dryers (i.e. things with motors) as they often have an interference suppression component on the mains input which could be using earth as part of the suppression circuit, but if one of those was 'playing up' then the mains would be tripping all the time.

The discussion is starting to suggest that the caravan RCD is at fault, and that the power supply is faulty so the house trips because the caravan doesn't. Any competent electrical contractor should have an RCD tester to check the caravan unit. The horrible Chinese MCBs and RCDs fitted in caravans are notoriously unreliable so that would be a good starting place. Schneider RCDs and MCBs are an almost identical size replacement for the Chinese beasts but it may involve some minor rewiring inside the power box.

 

[fusilierphil]

The comment above worries me. No item should have ANY leakage to earth, neither should the circuits assuming nothing connect to them. Given also that many items these days are double insulated and have only two core cable, how could that leakage to earth occur?
The only items that conceivably could have leakage are such as dishwashers, washing machines, and tumble dryers (i.e. things with motors) as they often have an interference suppression component on the mains input which could be using earth as part of the suppression circuit, but if one of those was 'playing up' then the mains would be tripping all the time.

The discussion is starting to suggest that the caravan RCD is at fault, and that the power supply is faulty so the house trips because the caravan doesn't. Any competent electrical contractor should have an RCD tester to check the caravan unit. The horrible Chinese MCBs and RCDs fitted in caravans are notoriously unreliable so that would be a good starting place. Schneider RCDs and MCBs are an almost identical size replacement for the Chinese beasts but it may involve some minor rewiring inside the power box.

Thank you for the info, I have changed the battery because it was past its best, I got a new lead to connect to the mains but this time I connected it to the CU in the garage and not the house as before and touch wood it has not tripped again, but I still intend to change the RCD in the caravan as suggested by you.

 

[Woodentop]

Thank you for the info, I have changed the battery because it was past its best, I got a new lead to connect to the mains but this time I connected it to the CU in the garage and not the house as before and touch wood it has not tripped again, but I still intend to change the RCD in the caravan as suggested by you.

Changing the RCD, the fiddly rewiring bit will be - if it is like my Bailey Pegasus was - replacing the connections from the output of the RCD to the inputs of the MCBs. Mine had purpose made insulated copper bus-bars and the position of the outputs of the RCD was different from the original. I used 2.5mm flex, with two identical length parallel strands each for L & N for the 16A breaker and one strand each for the 6A. You must use FLEX - solid core cable such as used in domestic wiring (6242Y) will vibrate and eventually break. If you have replaced your 2.5mm orange EHU cable then the old one can be cut and used and will fit the bill perfectly.

I must emphasize you should only venture into this area if you know <exactly> what you are doing and are competent to do the job.

 

[xtrailman]

The comment above worries me. No item should have ANY leakage to earth, neither should the circuits assuming nothing connect to them. Given also that many items these days are double insulated and have only two core cable, how could that leakage to earth occur?
The only items that conceivably could have leakage are such as dishwashers, washing machines, and tumble dryers (i.e. things with motors) as they often have an interference suppression component on the mains input which could be using earth as part of the suppression circuit, but if one of those was 'playing up' then the mains would be tripping all the time.

The discussion is starting to suggest that the caravan RCD is at fault, and that the power supply is faulty so the house trips because the caravan doesn't. Any competent electrical contractor should have an RCD tester to check the caravan unit. The horrible Chinese MCBs and RCDs fitted in caravans are notoriously unreliable so that would be a good starting place. Schneider RCDs and MCBs are an almost identical size replacement for the Chinese beasts but it may involve some minor rewiring inside the power box.

Leakage does happen nothing to worry about.

 

[Woodentop]

Leakage does happen nothing to worry about.

Pray tell where and how?

 

[xtrailman]

Sometimes between live and earth or earth and neutral, either one will trip a RCD if the leakage is high enough.

Try Google search for more details.

 

[ProfJohnL]

Ideally there should be no leakage of current in wiring or appliances, but the reality is there is no such thing as perfect insulation on wiring or in appliances so there is inevitable some leakage.

The question is the scale of these leakages, and when might they become a problem.

There is a rule of thumb that suggests the minimum value of the required insulation resistance (IR) which is determined by the normal working voltage: where the IR should be at east 1 megohm per 1000V with a minimum value of 1 megohm

Most mains appliances in the UK should exhibit at least 1Mohm of IR, but generally its well over and often beyond 20 megohm.

Physical and environmental factors will also play a part in affecting the performance of electrical insulation. Just for example humidity can provide a dielectric path if the ends of a stripped cable are exposed. crushing pressure or an unusually sharp bend on a cable will compress and thin the insulation which also reduces its insulation resistance. Beware of driving over EHU cables, or trapping wiring.

The performance of an appliances IR is one of the tests performed when the appliance is manufactured or subsequently tested. Portable Appliance Tests (PAT) incorporate an IR test.

RCD is a generic term used to describe automatic current disconnection devices that detect residual or leakage currents. These are installed between the appliance and the supply and can come in various forms described as:-

• RCCB ===Residual current operated circuit-breaker without integral overcurrent protection.
• RCBO===Residual current operated circuit-breaker with integral overcurrent protection.
• CBR==== Circuit-breaker incorporating residual current protection.
• SRCD=== Socket-outlet incorporating an RCD
• PRCD===Portable residual current device
• SRCBO==Socket-outlet incorporating an RCBO

In each case they monitor the current flowing in both the Live and Neutral conductors in the circuit, which should be exactly equal in both conductors. (Some versions also measure the absolute current flowing and will trip it the threshold is exceeded like a Miniature Circuit Breaker ) If a leakage fault occurs it means that some of the current in the circuit is finding an alternative route back to the supply and that imbalances the current in the L and N conductors.

Each RCD has a trip limit threshold which if the current imbalance between the L&N conductors exceeds the RCD's trip limit, the RCD should operate and disconnect the L&N load conductors from the supply.

Each RCD should have its trip limit and its disconnection time indicated on its body.

What can go wrong?
As cables get longer the there is a greater opportunity for IR values to combine which will reduce the total IR value for the cable - But this would apply to much longer installation runs than you would find in 99.99% of domestic and caravan installations. A properly trained electrical installer would o course check for this as part of their testing procedures.

As appliances all connect in parallel to the L&N conductors, the more appliances you connect their individual IR values will appear in parallel and reduce the over all IR value. Number of marginal appliances added together could reduce the IR value to the point where a sensitive RCD detects it and trips.

RCD's can with age or usage can move out of their specification and become over or under sensitive. which its why its important to periodically use the test button to confirm operation.

In general a normal caravan and EHU cable should not suffer with Insulation Resistance problems unless the wiring or an appliance does have a fault.

 

[Dustydog]

The RCD must trip in a micro second to protect life. There are strict performance regs laid down. Ones I have seen say
'High sensitivity' RCDs, rated 30mA or even 10mA, are designed to disconnect the supply within 40ms at 150mA and within 300ms at rated tripping current to protect the user.

In addition to Prof’s paper the point is they are there to save your life . One second of current can kill you putting your heart into atrial fibrillation, bingo , toast or brown bread

 

[Woodentop]

Ideally there should be no leakage of current in wiring or appliances, but the reality is there is no such thing as perfect insulation on wiring or in appliances so there is inevitable some leakage.

The question is the scale of these leakages, and when might they become a problem.

There is a rule of thumb that suggests the minimum value of the required insulation resistance (IR) which is determined by the normal working voltage: where the IR should be at east 1 megohm per 1000V with a minimum value of 1 megohm

Most mains appliances in the UK should exhibit at least 1Mohm of IR, but generally its well over and often beyond 20 megohm.

Physical and environmental factors will also play a part in affecting the performance of electrical insulation. Just for example humidity can provide a dielectric path if the ends of a stripped cable are exposed. crushing pressure or an unusually sharp bend on a cable will compress and thin the insulation which also reduces its insulation resistance. Beware of driving over EHU cables, or trapping wiring.

The performance of an appliances IR is one of the tests performed when the appliance is manufactured or subsequently tested. Portable Appliance Tests (PAT) incorporate an IR test.

RCD is a generic term used to describe automatic current disconnection devices that detect residual or leakage currents. These are installed between the appliance and the supply and can come in various forms described as:-

• RCCB ===Residual current operated circuit-breaker without integral overcurrent protection.
• RCBO===Residual current operated circuit-breaker with integral overcurrent protection.
• CBR==== Circuit-breaker incorporating residual current protection.
• SRCD=== Socket-outlet incorporating an RCD
• PRCD===Portable residual current device
• SRCBO==Socket-outlet incorporating an RCBO

In each case they monitor the current flowing in both the Live and Neutral conductors in the circuit, which should be exactly equal in both conductors. (Some versions also measure the absolute current flowing and will trip it the threshold is exceeded like a Miniature Circuit Breaker ) If a leakage fault occurs it means that some of the current in the circuit is finding an alternative route back to the supply and that imbalances the current in the L and N conductors.

Each RCD has a trip limit threshold which if the current imbalance between the L&N conductors exceeds the RCD's trip limit, the RCD should operate and disconnect the L&N load conductors from the supply.

Each RCD should have its trip limit and its disconnection time indicated on its body.

What can go wrong?
As cables get longer the there is a greater opportunity for IR values to combine which will reduce the total IR value for the cable - But this would apply to much longer installation runs than you would find in 99.99% of domestic and caravan installations. A properly trained electrical installer would o course check for this as part of their testing procedures.

As appliances all connect in parallel to the L&N conductors, the more appliances you connect their individual IR values will appear in parallel and reduce the over all IR value. Number of marginal appliances added together could reduce the IR value to the point where a sensitive RCD detects it and trips.

RCD's can with age or usage can move out of their specification and become over or under sensitive. which its why its important to periodically use the test button to confirm operation.

In general a normal caravan and EHU cable should not suffer with Insulation Resistance problems unless the wiring or an appliance does have a fault.

Thanks for that Prof, clearly supporting my comment in post 13.

One point: RCBOs as often used domestically nowadays are usually only single pole - they isolate the live but NOT the neutral.

###########################

The RCD must trip in a micro second to protect life. There are strict performance regs laid down. Ones I have seen say
'High sensitivity' RCDs, rated 30mA or even 10mA, are designed to disconnect the supply within 40ms at 150mA and within 300ms at rated tripping current to protect the user.

In addition to Prof’s paper the point is they are there to save your life . One second of current can kill you putting your heart into atrial fibrillation, bingo , toast or brown bread

If the trip needs to go in a microsecond, why is the spec 30mS, or was that a typo Dusty?

 

[bertieboy1]

I agree.

I agree.

What a load of rubbish there should be no leakage current whatsoever from any electrical appliance.

 

[xtrailman]

What a load of rubbish there should be no leakage current whatsoever from any electrical appliance.

Then why did we have to carry out PAT testing.

 

[Woodentop]

What a load of rubbish there should be no leakage current whatsoever from any electrical appliance.

...which is what I said at the start but I got shouted down.

######################################

Predominately PAT testing is to check that the earth is good, connected, and low resistance. That is why I always argued over why the PATman should test a wall-wart with a plastic earth pin - but he always did and passed the unit!

 

[Malx]

The comment above worries me. No item should have ANY leakage to earth, neither should the circuits assuming nothing connect to them. Given also that many items these days are double insulated and have only two core cable, how could that leakage to earth occur?
The only items that conceivably could have leakage are such as dishwashers, washing machines, and tumble dryers (i.e. things with motors) as they often have an interference suppression component on the mains input which could be using earth as part of the suppression circuit, but if one of those was 'playing up' then the mains would be tripping all the time.

The discussion is starting to suggest that the caravan RCD is at fault, and that the power supply is faulty so the house trips because the caravan doesn't. Any competent electrical contractor should have an RCD tester to check the caravan unit. The horrible Chinese MCBs and RCDs fitted in caravans are notoriously unreliable so that would be a good starting place. Schneider RCDs and MCBs are an almost identical size replacement for the Chinese beasts but it may involve some minor rewiring inside the power box.