Erratic tripping

[leggedit]

Hello, this my first post and it is from South Africa.

Our house has a concumer unit fitted with 20a trips all of which had worked well.

Recently have changed lawn mower and this is now tripping the circuit to the outside socket immediately switched on.

Mower does not trip if plugged into any internal socket. Therefore assumed trip was faulty.

However rewiring external circuit through another trip switch also causes a trip.

Old mower (of lower power ) does not trip at all.

New mower works ok elsewhere and at other houses so have concluded there may be a wiring problem on the outside circuit which is a spur with only two sockets.

However this only shows as a fault with this particular mower and I am puzzled as to explanation.

I will be getting a local electrician to do full checks but I would appreciate any advice or comment and hopefully explanation before contact so I can determine if they know what they are doing......

Many thanks in anticipation.

 

[leggedit]

Have just realised there is a second page and have read Marvo's detailed post after my reply.
Yes that makes a lot of sense and I will try to track down other sockets if any on that same spur.
However at times of tripping there were no other loads in use around the house as far as I am aware.
re your 4 points
1 it tripped immediately so short one sec bursts not possible
2 there really wasn't any load from the blades in grass as lawn was short from a recent cut from another machine.
3 Whoops already fitted a 25A breaker which caused no concern when bought from main wholesaler or from electrician who fitted.
4 yes I had asumed that was the case and will check to see if I can confirm by plugging light into all sockets around house when breaker is off and then if one is dead switch on breaker. crude but should do the trick

Yes the sparkie did the job but I am still not sure what was the cause of problem

I will remember point 3 if I need to sell or get certification and replace old breaker before inspection.

May be in Cape Town mid december Marvo and may try to buy you a beer for your very clear explanation and suggestions - Thank you

 

[leggedit]

Have just realised there is a second page and have read Marvo's detailed post after my reply.
Yes that makes a lot of sense and I will try to track down other sockets if any on that same spur.
However at times of tripping there were no other loads in use around the house as far as I am aware.
re your 4 points
1 it tripped immediately so short one sec bursts not possible
2 there really wasn't any load from the blades in grass as lawn was short from a recent cut from another machine.
3 Whoops already fitted a 25A breaker which caused no concern when bought from main wholesaler or from electrician who fitted.
4 yes I had asumed that was the case and will check to see if I can confirm by plugging light into all sockets around house when breaker is off and then if one is dead switch on breaker. crude but should do the trick

Yes the sparkie did the job but I am still not sure what was the cause of problem

I will remember point 3 if I need to sell or get certification and replace old breaker before inspection.

May be in Cape Town mid december Marvo and may try to buy you a beer for your very clear explanation and suggestions - Thank you

 

[leggedit]

ps apologies for double post not sure what I did to cause it.

 

[Wiredspark]

Erratic tripping eh? Done some of that at college years ago. I've moved away from that now

 

[Darkwood]

Get a push mower power free, keeps you fit and is energy efficient....

 

[MFHEng]

Get a push mower power free, keeps you fit and is energy efficient....

Or a sheep, they fertilise the grass as they trim it. Win win situation

 

[Marvo]

.......3 Whoops already fitted a 25A breaker which caused no concern when bought from main wholesaler or from electrician who fitted.......

The 'electrician' who just installed a 25 amp MCB on a 2.5mm [FONT=&quot]²[/FONT] socket circuit obviously feels less than nothing for the regulations. There are cases where even a 20 Amp breaker is too much for a socket circuit if the cabling is running in a hot roof void (above 40 [FONT=&quot]°[/FONT]C) or if it's buried in roof insulation. The cable derating tables in SANS 0142 would require the circuit to be 4mm [FONT=&quot]²[/FONT] cable on a 20Amp breaker.

Did the sparky issue you with a certificate (COC) for the work he did? He should have done so if he was registered.

Enjoy your holiday in Cape Town if you make it down here. It's still a bit chilly at the moment (less than 30 °C today but should warm up soon

 

[Jimmy Boy]

Not picking holes for the sake of it but I am curious to hear the claim that an MCB will only trip on a L/N fault ?..So if you put a nail through a cable and it shorts out L/E your saying it won't trip Pushrod ?

 

[pushrod]

Not picking holes for the sake of it but I am curious to hear the claim that an MCB will only trip on a L/N fault ?..So if you put a nail through a cable and it shorts out L/E your saying it won't trip Pushrod ?

Hi Steve, no probs shows people at least read what i say Have read thru the post i think you are referring to and, because i was trying not to be too wordy, i agree it is open to misinterpretation. You are obviously right that the pfc from an earth fault can take out the mcb . What i meant to convey was that if just the mcb is tripping and the rcd is not, then it is a L/N fault (or overload) . I'm a pretty slow typer and sometimes i think explanations get a bit lost in efforts to get it posted

 

[Jimmy Boy]

No problem matey I was genuinely curious