New Hagar Dual RCD board keeps tripping out.

[Slywolf]

Hi all.
This is my first post in the forums.

I am almost at the end of my 3rd year at college, and don't yet own a multifunction tester so cannot supply any results to help diagnose this fault. (Something I hope to be able to buy next month after my birthday :wink_smile: ). I will be giving it a test and inspect once I have bought test kit;
I have just done a consumer unit replacement for my parents as it was badly in need of doing, my dad quickly fitted a very cheap Clipsal board about 5 years ago when they moved in and started renovations, now it is vastly undersized, too many cables in each MCB even found a 16A protecting 1mm lighting circuit and no bonding.

I changed the board to a new Hagar Dual RCD board ( 2 x 63A 30mA, 100A main switch on a TT system), I was called back about half 11 last night as they went to have a shower and one of the RCD's tripped (Layout of this board is main switch is far right, the left RCD supplies 6A, 6A, 32A, 32A, 40A, 40A, and the RCD closest the Main switch supplies 6A, 6A, 16A, 32A, 40A, 40A), the tripped RCD was furthest from the main switch (on the left of the board). There are 2 showers connected via this RCD and operating either would cause it to trip, I thought maybe neutral in the wrong bar but not the case, I tried swapping the RCD's over and still the problem exists; I then decided to swap the showers from one side of the board to the other and swap the other 2 40A circuits back onto the side of the board that seemed faulty, this solved the problem and the board powered up fine and both showers worked.

Annoyingly got a phone call this morning saying the same RCD had just tripped out again, obviously not the showers now. Has anyone any thoughts; I am about to head over there now and check lighting points and socket outlets to see if anything is visibly obvious.

This is one of my first real life fault finding exercises outside of college and without test equipment I can see this one being really annoying to solve.

Thanks all,
Sly

 

[telectrix]

possible you have a borrowed neutral on lighting, specifically 2 way landing light. could it be that when they go for a shower, they are switchi8ng on landing light, causing the trip????? try puttin both? lighting circuits on the same RCD.

 

[dave274]

switch the mcb's off and check each circuit one at a time to id which circuit is faulty. you shouldn't really be changing consumer units without testing it before re-energising it and notifying it even for your parents.

 

[Slywolf]

Thanks for the pointers, I'll try putting the lighting together on one RCD and see it that helps; I didn't really want to do the change over of the consumer unit till I have my tester but they are building an annex in the garden and the new sub main needed installing. (Note: new sub main doesn't run through this board, but through a 45A fused switch)

Thanks again

 

[Fox]

Can you borrow a tester from college to narrow the fault down? It will be far quicker to find unless you get lucky...

 

[cobrauk]

Did you have rcd's before ? if not could be a heater circuit cooker or anything with element that is on its way out

 

[chopper76]

2 showers on a 63a rcd, no diversity for water heating

 

[imago]

Has anyone any thoughts;

Aside from wondering about the sort of sentences they hand out for patricide or matricide these days, no.

 

[Slywolf]

Been back to the job to sort the problem. Seems the house has some bad wiring, 2 and 3 way lighting was wired wrong, upstairs and downstairs lighting circuits seem to share a neutral. I have put all lighting circuits on the same RCD, I haven't yet managed to locate the joined neutrals but have at least managed to stop it tripping out.

Being it is the parents house I have the chance to go back and look at the problem further, most of the house has been rewired but parts of the old upstairs lighting circuit still remain, I believe this is where the problem lies.

Thanks all for suggestions, its quite a large house and helped to narrow down where to look.

 

[markc123]

Common fault in older properties mate - let this job be an education because it wont be the last time you come across it in your career and i can assure you of that.

Read telectrix post at #2 again, he stated this. Hallway/landing lights are your first port of call to find the pesky borrowed neutral.

Good luck.

 

[PEM]

Ok, sorry to be a kill joy but after 3 years at college what you have done is:-

1. Install a CU without any pre or post testing!
2. CU change requires Building Regs notification before works start or you "self certify" I presume you can't.
3. I presume no test certification.

In effect just about everything that you could do wrong you did.

Did your college teach you nothing!!!

Not having test gear is lame as you can hire them!!!

Be ashamed and go back to school or better still become a plumber.

If this sounds harsh good.

You've put people at risk.

 

[PEG]

Pems narrative is going to sound harsh,but you have to accept where you are is where you have put yourself. Such work,undertaken without neccessary test gear,is risky at best.Picture yourself attempting to work as a taxi driver in a town you don't know,with no sat-nav,a to z or directions.That is where you are now,driving around in circles asking strangers for directions...Maybe plumbing was bad career advice,just take the career you have chosen a bit more seriously.If you do so,in a few years time,you will be using this cautionary tale to instruct another up-and-coming electrician.Good luck.

 

[N6rul]

good guys

Mate, its dangerous!!! What your doing!!! I always do a full test of a circuit before a consumer change. Takes time and know how!! At least I know im doing it the right way so my job is safe before energising. Hope you learn from this!!

 

[TaffyDuck]

Ok, sorry to be a kill joy but after 3 years at college what you have done is:-

1. Install a CU without any pre or post testing!
2. CU change requires Building Regs notification before works start or you "self certify" I presume you can't.
3. I presume no test certification.

In effect just about everything that you could do wrong you did.

Did your college teach you nothing!!!

Not having test gear is lame as you can hire them!!!

Be ashamed and go back to school or better still become a plumber.

If this sounds harsh good.

You've put people at risk.

100% right. So much for college, lets hope his parents live to tell the tale.

Get it tested now by somebody who knows what they are doing.