Single phase tripping out

[neilarmo]

Hi mains leccy is tripping out on consumer unit in dad's shed. Electrician has made it ultra safe, now it won't even run a 9" grinder, and you can forget the pickhill bantam welder.


Main trip in box is going every time, it is 100 amp switch with in built trip and test button. Text on switch says 0.1mA, what rating is more suitable for workshop applications.
Have a look at yours tomorrow please, or any educated comments welcome.

Thanks,
Neil

 

[Iain Westland]

sounds like the spark didn't know what your draw would be,

 

[neilarmo]

It's not the draw (nowhere near 100 amp) its the trip too sensitive.

 

[rtbcomp]

Are we talking MCB (current trip) or RCD (earth leakage trip)?

If it's an RCD check that one of the load's live or neutral isn't connected to the line side.

 

[Iain Westland]

all your sockets are on a single 100A or is it the main thats tripping and not the smaller rated breakers?

 

[SirDick Diodenob esquire]

Have another look at the RRCB 0.1mA is a bit low , 10mA is lowest I have ever seen and even that would be way too low for a workshop or in house , its probably 100mA ? You can get RCCBs rated up to 1000mA which would ignore any leakage up to 1 amp but this is also way over the level which can cause electrocution so it wouldnt comply with the wiring regs and these are not used for domestic final circuit distribution . Its unlikely that all the tools in your workshop have an earth leakage but it is possible . First I would get the RCCB checked , what make is it ? These things do fail as they have electronics inside them and in recent years there has been an insurgance of nasty ones coming from the far east , the good ones are still made in France and Germany but even the major manufacturers are now making most of them in China but there has been a lot of counterfeiting of the major brands . Get the wiring checked again and finally you may have to get the wiring checked on each tool . Have you actually tried your Bantam to see if it trips and is it going straight onto the 100amp breaker or do you have another mcb in between ? Finally its also possible to incorrectly wire an RCCB but if your electrician is qualified its unlikely he has made a mistake in this area . Is there a lot of moisture or condensation in the shed ?

 

[Iain Westland]

im still bothered by the 100A, I have 32A 3P and 10A 1P after my 100A. Even in the studio I wired lights n sockets up separate.

 

[neilarmo]

A comprehensive reply Sir Dick, thanks.
Electrician is qualified but may have been having a bad day
Last week when another circuit was wired in (not causing original problem) when the knockout hole was made the whole unit jumped off the wall. It was screwed into chipboard with half inch no.8 screws, not man enough to hold a coat hook!

RCCB may be 1mA but is no more, I will look again tomorrow.
N

Edit
100A is main trip in box, there are other 32A, 16A and 8A trips in there, all through the main 100A switch. Don't panic!

 

[Iain Westland]

feel better now

 

[morph]

What type of trips are they? B or C curve? The spark who did my shed put a B type on the 13amp socket ring and it tripped out every time i switched a 110v transformer on. It got changed to a C type and has been fine for over 10 years. I bet he put a domestic B type thats not designed to take a 9"!!

 

[scarecrow]

my grinder will also trip a 16amp switch as I had one set of plugs for hand drills and bench grinder and the odd inspection lamp

 

[brightspark]

it will be 100amp double pole possibly 100 ma trip. but it should be a 30 ma trip. the 100 amp doesnt mean that it will break at that current load .it just means that it will carry that amount of current at full load . u more than likely have earth leakage on wiring or an apliance to cause it to trip no point in guessing or theorising just get the elecrician back and do a megger test on circuits it should be easy to solve

 

[neilarmo]

brightspark, electrician being a pratt and not coming back.
all appliances work fine at my place next door.

I have a number of approaches now, thanks.

Update after breakfast and a think.
Trip is Hager CE 284U RCCD 100A 0.1A (sorry to cause confusion)


Will let you know...

 

[SirDick Diodenob esquire]

Neil , Brightspark is right that your electrician should have used a 30mA rccb to comply with the latest wiring regs but the Hager unit you have is a 100amp double pole isolator with 100mA protection against earth leakage it does not have built in protection against overload or short circuit faults whereas your 32amp and other mcbs have , this is all ok except for the 100mA earth leakage protection on the rccb .

 

[brightspark]

Neil , Brightspark is right that your electrician should have used a 30mA rccb to comply with the latest wiring regs but the Hager unit you have is a 100amp double pole isolator with 100mA protection against earth leakage it does not have built in protection against overload or short circuit faults whereas your 32amp and other mcbs have , this is all ok except for the 100mA earth leakage protection on the rccb .

as above if u have the 100ma trip fitted the 30ma is more sensitive . so theres definately earth leakage or current inbalance due to a faulty cable either in the fixed wiring circuits covered by the rcd or on an apliance an insulation check with megger is the only solution

 

[pauld]

Trip is Hager CE 284U RCCD 100A 0.1A

Yeah, to comply with the current regs then it should be 30mA RCD. My guess is that the earthing is TT (earth rod) and that is in there from pre 17th Ed... but even that doesn't quite add up as I would expect it to be a time delayed 100mA, which it isn't based on that part number.

Your issue might be as simple as something not quite wired correctly, like neutral and earth swapped somewhere (the imbalance of current in live and neutral would then cause a trip to occur).