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Discussion Starter #1 (Edited)
Removed the front cover from my now 4 year old “Dumb” Rolec wall box today.
I was ready to install a timer to allow delayed charge.
As soon as I removed the cover, my eyes quickly focused on the mess of the blue NEG terminal on the RCOB !.
As you can clearly see, the NEG cable has become over heated !.
I checked the terminal connection screw and expected to find it loose, but no it was tight strangely enough ?.
Of course I intend to replace it straight away !.
Can somebody please recommend a really good quality replacement unit.
I think a few members have fitted the “Garbo” breakers ?.
I would be extremely grateful if somebody can provide links to their suggestions please.
The current Rolec breaker was replaced after only two weeks of use for random tripping.
It would even trip when the car was NOT plugged in !.
It was fine until last week and the wall box tripped while charging.
Strange, I thought !.
But it reset okay and I have been charging the ZS EV fine for about a week.
Clearly, it was not okay of course.
I had a plug in hybrid for 4 years before the BEV and therefore wall box had an easier life then.
The much longer charge cycle of the ZS EV has proven too much I feel.
Here is a picture of the damage.
Needless to say, the yellow reset / test button does not work anymore !.
P.S. - That is the Sonoff Wi - Fi switching unit you can see hiding behind the RCOB.

0C3B2508-0E3E-4CB5-863F-68BB2447DC0F.jpeg
 

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Wow that’s only carrying the load and not switching it, must have had a very poor set of contacts in the breaker. Think I better check mine but at the moment it’s got an easy task with my PHEV but that’s gonna change soon.
 

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That wire looks way too thin to be carrying 30A or so! Or is this a granny cable outlet?
 

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Discussion Starter #4 (Edited)
That wire looks way too thin to be carrying 30A or so! Or is this a granny cable outlet?
Hi Paul - Which wire are you referring too ?.
The blue NEG cable with the rough temp tape job is the main 6mm incoming supply.
This photo may explain it a bit better !.
A8847F78-8597-4323-AE36-6E99CF53C72B.jpeg
 

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Wow that’s only carrying the load and not switching it, must have had a very poor set of contacts in the breaker. Think I better check mine but at the moment it’s got an easy task with my PHEV but that’s gonna change soon.
Best to check and replace with a better quality RCBO. There’s a thread on it on here.
 

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Discussion Starter #7
Best to check and replace with a better quality RCBO. There’s a thread on it on here.
Your totally correct of course !,
This was the “Newer” breaker supplied by Rolec about 4 years ago.
But I still believe there is better quality units to be purchased else where !.
After seeing this, I now intend to check my unit every 6 months !.
I am still experimenting with the Wi - Fi switching by command from my phone.
I quickly set a 15 min stop / start charge cycle this afternoon ( test purposes only ) and it worked fine !.
 

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Discussion Starter #11
the burned blue wire. it's hard to tell the scale, to be fair, it just seems a bit narrow to me from the picture.
Yeah - It's flat 6mm Twin & Earth cable okay.
When the NEW breaker is fitted early next week, I will try and get a better photo of the extent of the damage.
When the wire was removed from the breaker, you could smell burning had been taking place inside of the switch !.
When the wall box tripped unexpectedly one day last week, I should have trusted my "Gut" and removed the front cover and do a basic check.
I do feel that now we are charging the ZS EV it has placed a much larger load on the wall box.
Our previous plug in hybrid charged much slower and would only take 2.15mins to fill from empty to full !.
Much different to the ZS EV that can take 6 hours + and at a much higher load.
It will not take long to find any weakness in a wall box when doing this.
 

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Discussion Starter #12
Hi - The new RCOB arrived from Rolec.
I said I would share a few photo's of the poor condition of the burnt old unit.
There was a pungent smell of burning evident, the moment the front cover was removed !.
The pictures / condition of the old unit totally speak's for it's self, I think you would agree.
All of the cables on the RCOB where tight prior to removing, so I don't believe it was a connection issue that caused the problem.
I can only presume it is poor quality internal connections of the RCOB then !.
As you can see in the picture the blue ( Neg ) cable had been getting extremely hot.
At least, the first inch of the multi strand 6mm blue ( Neg ) cable was very stiff and hard to bend due to the excess heat produced.
Fortunately, there was enough slack in the cable to enable me to pull more of the 6mm T&E into the wall box and then trim almost 2 inches from the ends of each single core of each cable, to ensure I had new fresh strands to "Make Off" to the new RCOB.
Should this happen again, I will have to replace the T&E supply wire because there is not enough spare cable now to trim back once again.
I would also consider upgrading to a 10mm T&E cable as well.
A bit O.T.T. you may think, but I would definitely consider doing this.
Only speaking for myself here of course, but I am not a big fan of the multi strand flex, I think the solid core cable when turned back on itself, achieves a better connection on the terminal contacts.
I have tightened ALL of the terminals on the new breaker until I can obtain NO more purchase from a good quality electrical screw driver !.
I then left the terminals rest for about 20 mins and then returned to each terminal again, to obtain a VERY small amount of extra purchase on each terminal screw.
I have also checked every other connection I can find in the wall box and they all appear to be good and tight !.
Then, I refitted the front cover and reconnected the supply to the wall box.
Using the "Test" switch on the RCOB to ensure it was tripping correctly on demand and all working fine !.
Then plugged in the car and requested a charge from the App on my phone.
I only conducted a quick 5 min test, then ended the charge session from my phone, all appears to be working fine at the moment.
I will remove the front cover again in about 2 weeks and firstly carry out a visual check of the RCOB for any signs of burning, then also check tighten ALL four connection terminals once again !.
I am concerned that I only found out about this RCOB problem by pure chance really.
Removing the front cover to carry out something completely different, revealed the issue with the over heating of the RCOB.
The ONLY indication I received that something maybe a problem, was 3 days earlier I went to the car to remove the charging cable after a charge and noticed that the wall box had tripped ?.
This was the first time that the RCOB had tripped for the first time in almost four years of previous use.
The "Test" switch function on the old RCOB must have stopped working then I guess ?.
If this new type of Rolec supplied "Green" RCOB starts to display ANY signs of deterioration quickly, I will be replacing it with an alternative type of unit altogether.
The first photo displays the OLD unit.
Next three photo's are the new unit installed.

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