Tripping issue with new installed 13 Way Dual Split Consumer Unit 2x100A RCDs (Type A) + 12 MCBs + SPD

[Chippyminton0]

Hi, I need some help locating and resolving a fault on a new consumer unit.
I removed an existing plastic MK Sentry duel 63amp RCD unit which worked fine and replaced it with a new metal MK Sentry duel 100amp RCD unit with a SPD.

No 1 RCD I had 5 circuits. No problems all worked fine.

No 2 rcd I had 4 circuits. (There are no appliances plugged in) when I put any load on any of the circuits it trips out No 1 RCD.
When number 1 trips, number 2 doesn't but the voltage at number 2 drops to 187v
I have removed all the circuits entirely and tried each on their own on No 2 rcd and the same thing happens.
The original board (which had no problems)had 2 x 64 amp RCDs which I know work. I replaced the 100 amp pair with these and still the same problem. I have put the 100 amp pair back on but swapped them around, still the same problem.

I have removed the surge protector, same thing happens

I have now put all the circuits on to number 1 RCD and every thing works fine with no tripping. However I don't want them all on 1 rcd, I can't afford rcbo's yet. But more importantly there is still an issue there that needs resolving.

Any ideas what it might be?

I apreciate any help

 

[HappyHippyDad]

A picture with all the cables in would be better.
You may have one of the neutrals from the right RCD in the left hand neutral block.

 

[mainline]

As above, you have most probably used the wrong neutral bar.

 

[brianmoooore]

Have you split any lighting circuit that was on one MCB into two circuits on two MCBs?

 

[Chippyminton0]

A picture with all the cables in would be better.
You may have one of the neutrals from the right RCD in the left hand neutral block.

Hi Happy Hippy dad, thankyou for your reply.

Hi, I need some help locating and resolving a fault on a new consumer unit.
I removed an existing plastic MK Sentry duel 63amp RCD unit which worked fine and replaced it with a new metal MK Sentry duel 100amp RCD unit with a SPD.

No 1 RCD I had 5 circuits. No problems all worked fine.

No 2 rcd I had 4 circuits. (There are no appliances plugged in) when I put any load on any of the circuits it trips out No 1 RCD.
When number 1 trips, number 2 doesn't but the voltage at number 2 drops to 187v
I have removed all the circuits entirely and tried each on their own on No 2 rcd and the same thing happens.
The original board (which had no problems)had 2 x 64 amp RCDs which I know work. I replaced the 100 amp pair with these and still the same problem. I have put the 100 amp pair back on but swapped them around, still the same problem.

I have removed the surge protector, same thing happens

I have now put all the circuits on to number 1 RCD and every thing works fine with no tripping. However I don't want them all on 1 rcd, I can't afford rcbo's yet. But more importantly there is still an issue there that needs resolving.

Any ideas what it might be?

I apreciate any help

The 16amp mcb protected by rcd has just been put in to show the symptoms of the fault. It's 2.5mm cable and run to a double socket. The load on it is a makita charger with nothing on charge.

Have you split any lighting circuit that was on one MCB into two circuits on two MCBs?

Thanks for your reply Brian. No I havnt. I have added a video and photo

 

[brianmoooore]

Thanks for your reply Brian. No I havnt. I have added a video and photo

Won't be the common 'borrowed neutral' problem often found on stairs lighting circuits, so, in that case, HappyHippyDad is likely to be on the money

 

[DefyG]

Looks like the neutral link for the RHS RCD is taken from the wrong Neutral bar at the top (In position 8?)
It should be from the LHS Neutral bar.
The original photo shows 4No thick Blue link cables whereas the video shows 3 but 2No in the middle neutral bar.

 

[brianmoooore]

Agree. There are three neutrals in the LH neutral bar, but there should be four. One in from the main switch, one to the SP, and one each to the two RCDs.

 

[mainline]

Maybe better to call a decent electrician in to install it properly.

 

[littlespark]

I thought hes done pretty well for a non pro.

I've seen worse in the wild by those registered with a CPS.

Its just been simply a case of the wrong neutral bar, and hopefully its fixed now.



Of course, though, it will need tested and certified....

 

[mainline]

I thought hes done pretty well for a non pro.

What makes you think he's not a pro ? Doing such a nice job.

I've seen worse in the wild by those registered with a CPS.

I don't know what that's got to do with it.

Its just been simply a case of the wrong neutral bar, and hopefully its fixed now.

The first pic showed Cu pre wired initially which was then altered I wouldn't call that a simple mistake,

Of course, though, it will need tested and certified....

It needed to be tested before being energised not after.

 

[Chippyminton0]

Thanks littlespark, I'm doing my house up, ive rewired most of it just the ground floor ring left to do. The wiring I did in the consumer unit doesn't look too Tudy mainly because I've been moving the circuits about trying to work this problem out. I can tidy it up now thanks to you guy . The neutrals in the board came as they were from the manufacturer. I have read that since honey well took over MK and then licenced it out to a chinese firm that the quality had gone right down hill. I wouldn't expect them to make a mistake like that.
Any way once the wiring is finished I am going to get it tested by an electrician.
I have one more question that maybe you could help with.
I have an unprotected mcb fed from the main switch. It's not protected by the spd. I want to run a supply through an isolator near the CU and out to the garage where it would be protected by a bidirectional rcbo. Is that permitted, does it conflict in anyway with the spd?

 

[Chippyminton0]

Looks like the neutral link for the RHS RCD is taken from the wrong Neutral bar at the top (In position 8?)
It should be from the LHS Neutral bar.
The original photo shows 4No thick Blue link cables whereas the video shows 3 but 2No in the middle neutral bar.

That's done the job, thankyou.

 

[Chippyminton0]

What makes you think he's not a pro ?


I don't know what that's got to do with it.

The first pic showed Cu pre wired initially which was then altered I wouldn't call that a simple mistake,

It needed to be tested before being energised not after.

Hi Thanks for your comments. Just to be clear the first pic was a screen shot from screwfix's website. It was a generic photo of the type of CU which i bought. The second one was my consumer unit, although I had not removed any of the neutrals from the neutral bar. The way you see it was the way I received it. I knew there was a neutral issue because it just made sense but it didn't occur to me that a manufacturer like MK would make an error like that. Which is why it wasn't obvious to me. Sometimes another set of eye will see the immediately even if it is staring me in the face. For peice of mind the whole house wireing will be tested. I apreciate your comment

 

[Chippyminton0]

Hi, I need some help locating and resolving a fault on a new consumer unit.
I removed an existing plastic MK Sentry duel 63amp RCD unit which worked fine and replaced it with a new metal MK Sentry duel 100amp RCD unit with a SPD.

No 1 RCD I had 5 circuits. No problems all worked fine.

No 2 rcd I had 4 circuits. (There are no appliances plugged in) when I put any load on any of the circuits it trips out No 1 RCD.
When number 1 trips, number 2 doesn't but the voltage at number 2 drops to 187v
I have removed all the circuits entirely and tried each on their own on No 2 rcd and the same thing happens.
The original board (which had no problems)had 2 x 64 amp RCDs which I know work. I replaced the 100 amp pair with these and still the same problem. I have put the 100 amp pair back on but swapped them around, still the same problem.

I have removed the surge protector, same thing happens

I have now put all the circuits on to number 1 RCD and every thing works fine with no tripping. However I don't want them all on 1 rcd, I can't afford rcbo's yet. But more importantly there is still an issue there that needs resolving.

Any ideas what it might be?

I apreciate any help

It works a treat now, thankyou for all your help. I'm not sure I would bother with MK anything in future