Earth Leakage Breaker (RCD) Tripping

[ACEsterhuizen]

Same here Leecatt, at 50 years old and 30 years in the business I also tip my hat to Andy and his vast knowledge, realized again that I am not even remotely close to his (and a lot of others) level (of expertise). Respect.

[Justloadit]

Thanks @Andyd.
A well laid out post with all the loose bits of information in one place.

[AndyD]

Thanks guys for the kind comments, glad it might be useful. Leecatt, you're very welcome to use it/reproduce it freely under the Creative Commons licence terms which applies to content on the forum in general. Feel free to add info to this thread as well if you like.

[ACEsterhuizen]

Ahem, uhmm, which ramp tester would you recommend Andy and where can i buy one....? (can this text get any smalller...)

[AndyD]

I stumbled across these a while back and I bought a couple of for my guys. At R1.5K they're a bargain and Uni-T testers have a decent reputation even though they're not a high-end brand. I see on the same website they also have a Major Tech 5410 which is a rebranded Kew/Kyoritsu for just over R10K. I'm guessing it can test a wider range of RCD's such as versions with time delay or S-type etc but if you're working mainly in the domestic market it probably wouldn't warrant paying the extra.

Thing is once you're paying much more than R10K for an RCD tester nowadays you might as well look at a full MFT (multifunction tester) which is a PSC, megger, loop impedance and RCD testers all rolled into one like this one for example.

[Houses4Rent]

Question: My electrician said:

"It is optional to have the lights and/or geyser on ELU but also not a must. This is normally left at the discretion of the tenant/owner."

Is that correct and not regulated at all?

[Dave A]

It is optional to have the lights and/or geyser on ELU but also not a must.

Correct, with some conditions attached.

For example, if there is a ceiling fan on the light circuit, the fan must either have an isolator within arms reach, or the light circuit must be on earth leakage. (See 6.16.1.4 of SANS 10142-1)

When it comes to fixed appliances (including geysers & luminaires) in zone 1 or zone 2 in a bathroom, if it is not a class II appliance it has to be on earth leakage. (See Table 7.1 of SANS 10142-1 )

[DieterT]

Question: My electrician said:

"It is optional to have the lights and/or geyser on ELU but also not a must. This is normally left at the discretion of the tenant/owner."

Is that correct and not regulated at all?

If I was the tenant/owner and the electrician said to me

"It is optional to have the lights and/or geyser on ELU but also not a must. This is normally left at the discretion of the tenant/owner."

I would tell him to get the out!

Of course it is regulated. Conditions has to be met as mentioned. Some parts of the installation has to be under earth leakage and some parts not, should it meet the required conditions.
Nowhere ever was a choice ever given to the tenant/owner what has and does not have to be under earth leakage.
Maybe it could be that he found the lights and geyser to be effectively earthed and thus primary protection is adhered to and then only he could recommend to you in order to avoid nuisance tripping to have them removed from earth leakage or recommend for extra protection and to avoid nuisance tripping to have multiple ELUs in the DB board. If this is not the case then this electrician is "besig om n lat vir sy gat te pluk" and I hope for every job he does for you that he gives you a CoC

I have seen this way too many times. Earth leakage tripping, get to the house and find everything is wired under earth leakage (most of the time because it was some MnT job and they do so to cover themselves)
Sparky then goes and rewires the DB so it's just the plugs under earth leakage and the rest above....you ask what is wrong with this picture? The sparky never gone to check the primary form of protection. In effect taking secondary form of protection away, there is no more protection. But you say I can see the earth connected to the appliance/geyser/lights, but is it really, is the earth resistance such that should a fault occur and you are touching the conductive surface that, that fault condition will dissipate to earth via the earth connection, or through you as person to earth? and or is the earth resistance as such should a fault occur the circuit breaker would trip (yes a poor earth influences the CB from tripping as per designed curve)

Did the sparky check that before rewiring the DB in order to stop the nuisance tripping? I tell you most probably not, cause most of them can't even get it right on the CoC.
Do yourself a favour and watch next time someone does a CoC if they are testing the earth resistance from incoming earth to each point of consumption and conductive surfaces for earth continuity and earth resistance.

[Houses4Rent]

Thanks, that is all a bit too high for laymen like me. The EL tripped without any apparent reason. That is when sparky removed lights from EL.

"We took the lights off from earth leakage which could be the cause of the power tripping. The hot water cylinder was not on Earth leakage. "

[AndyD]

Thanks, that is all a bit too high for laymen like me. The EL tripped without any apparent reason. That is when sparky removed lights from EL.

"We took the lights off from earth leakage which could be the cause of the power tripping. The hot water cylinder was not on Earth leakage. "

I would personally say a circuit should not be removed from the earth leakage for 2 reasons;
Firstly the level of protection on that circuit has been reduced to overload only meaning it's now less safe than it was originally.
Secondly if it's causing the earth leakage to trip then there's nearly always a fault that needs actually finding and remedying rather than a half-assed workaround.

The earth leakage offers a fair to good level of fire protection, if there's a poor termination that's overheating or burning or some kind of arcing fault the earth leakage will almost always by the protective device that trips long in advanced of the 10A or 20A circuit breaker. Removing circuits from the earth leakage breaker because of a tripping problem is something I'd expect from a DIY'er but I hold electricians to higher standards and hope it's something they wouldn't do regardless of whether the regs specifically forbid it or not. The regs are the absolute minimum permissible standard and not to be considered pinnacle of electrical good practice.

The fact is however that probably in the majority of cases that a circuit is removed from the RCD because it's causing tripping it would be against the regs because the circuit itself or the fixed appliance has a fault or intermittent fault such as low insulation which would be below the allowed value stated in the regs.

There's many options available other than removing a circuit from an earth leakage breaker such as;

• Find the fault.
• Redesign the circuit if there's high standing/functional leakage.
• Find the damn fault.
• Install an RCBO for that circuit.
• Install a second RCD an split the DB circuits accordingly.
• Did I mention find the fault?

Earth leakage faults are often caused by;

1. Rodent damage.
2. Insect infestation.
3. Water ingress
4. Physical damage or excessive wear and tear to cables or a part of an appliance.
5. Poor terminations or other types of arcing faults.

In all of these cases just removing the circuit from the earth leakage is asking for trouble.