Use of Residual Current Circuit Breaker

[Jabberwocky]

Afternoon all,

I have been having a conversation with @Grey one on the merits of using the RCCB. That conversation has left us both a little confused (not difficult in my case!).
The Supplement that comes with the Cali says that when you connect to the mains you should switch the RCCB on after connection and that before you disconnect you should switch it off.

Can someone tell us why we shouldn't just leave it switched on. (as I have done to date)

(I recall seeing something on this matter a few weeks ago but can't find it sorry)

 

[Loz]

It's a bit over cautious to be honest, as long as you don't have any heavy load running in the van at the time you pull it, it would be okay.

 

[larrylamb]

It is however good practice to use the test button every so often.

 

[Jabberwocky]

It is however good practice to use the test button every so often.

If I press the test button what should I expect to happen?

 

[Cumbrian_Cali]

The theory behind switching the RCCB off before disconnecting the power cable is so that the plug is not disconnected under load.

If the plug is disconnected under load then an arc can occur which, through time can damage the plug/socket.
The arc also has the potential to cause burns to the person disconnecting the cable.

 

[Cumbrian_Cali]

When you press the test button with the hook up supply plugged in and switched on the following should occur;
• The RCCB switch should flip to the "off" position.
• the electrical supply to the mains powered devices in the van will be isolated from the supply.

 

[AlanC]

The theory behind switching the RCCB off before disconnecting the power cable is so that the plug is not disconnected under load.

If the plug is disconnected under load then an arc can occur which, through time can damage the plug/socket.
The arc also has the potential to cause burns to the person disconnecting the cable.

In principle this is correct.

However, an arc of that magnitude would indicate a massive current draw in the van. Most EHU posts are rated at either 6 or 10 amps and the post RCB would trip if a higher current was being drawn.

Given the van only has a battery charger and fridge that may - or - may not be running, I doubt there will be any arc, much less one that can damage the person pulling the plug out.

Alan

 

[andyinluton]

You shouldn't really be pulling the plug out whilst the cable is live anyway, it should be isolated at the other end before you disconnect at the van.

 

[Cumbrian_Cali]

In principle this is correct.

However, an arc of that magnitude would indicate a massive current draw in the van. Most EHU posts are rated at either 6 or 10 amps and the post RCB would trip if a higher current was being drawn.

Given the van only has a battery charger and fridge that may - or - may not be running, I doubt there will be any arc, much less one that can damage the person pulling the plug out.

Alan

That's why I said the theory behind the instruction.
Just answering the OPs question.

 

[DM]

The RCCD serves two purposes. One is to protect users in the event of any appliance faults that may result in users touching live wires / surfaces. The RCCD is a very sensitive device that will detect any difference in the current flowing in the live and neutral wires and will disconnect the feed if a difference is detected (i.e. there is current flowing through a person !!. It also acts as a manual isolation switch which disconnects the external hook-up from the wiring (and any connected appliances in the van).

Strictly, the ideal disconnection procedure would be:
i) turn of the RCCD manually (this ensures no current is flowing)
ii) disconnect your hook-up cable at the post end (so you cannot drop a live cable end in a puddle)
iii) disconnect your hook-up cable from the van

The above procedure is best practice and will protect the sockets at both ends from arcing. I know all this but I just leave mine switched on at the van permanently. I would always disconnect and stow any electrical appliances within the van anyway before disconnecting so that only leaves the charging circuitry which is highly unlikely to be drawing a significant current after a few hours on hook-up.

I do however disconnect at the post first.

 

[Cumbrian_Cali]

You shouldn't really be pulling the plug out whilst the cable is live anyway, it should be isolated at the other end before you disconnect at the van.

The instruction for the Cali owner is a cover-all that doesn't then need to go into detail about different hookup designs on different sites, some with and some possibly without switches. Some with red handles some with black handles etc etc.

 

[Cumbrian_Cali]

A link to a video on arc-flash for those interested.

 

[El Greco]

OMG! that's the same control panel as in my Cali. He must have left the fridge on, what a dummy!!!

 

[larrylamb]

Woe betide a caravanner unplugging whilst their 50" plasma is still on.

 

[Jabberwocky]

I do however disconnect at the post first.

Me too - always!

 

[sidepod]

In principle this is correct.

However, an arc of that magnitude would indicate a massive current draw in the van. Most EHU posts are rated at either 6 or 10 amps and the post RCB would trip if a higher current was being drawn.

Given the van only has a battery charger and fridge that may - or - may not be running, I doubt there will be any arc, much less one that can damage the person pulling the plug out.

Alan

So how do you think most domestic gas explosions are caused? From the tiny arc caused by the light switch. Not much current there either.

 

[DM]

So how do you think most domestic gas explosions are caused? From the tiny arc caused by the light switch. Not much current there either.

Not sure where you're going with this @sidepod . Are you suggesting that the RCD is protecting against a gas explosion? The RCD is a switch. Switches can arc. VW locates the switch close to the gas supply. The logical conclusion of your argument is that the power should always be isolated at the post as the switch itself is a hazard.

 

[sidepod]

No. I'm disagreeing with Alan when he says there wouldn't be be much of an arc, much less one that could damage a person, when making/breaking an electrical supply.

I'm not bonkers enough to start suggesting there is a gas hazard on your Cali !!!!

 

[Loz]

I think, if there is going to be any arc, it's better outside on the post where it's plugged in...

 

[larrylamb]

Blimey, how far do we have to go with this, it's quite simple.

 

[briwy]

Just get a couple of Roger's solar panels then no need for any hookup. Problem solved

 

[Jabberwocky]

Well, I never realised I had asked such a contentious question. That said all contribution is good. Thanks. Just going to switch RCCB off as insurance. Just hope I remember so that when I next hook up I don't have to post here asking why the control panel shows no hook up .