Some time back i read (think) Plonkster and TTT having a debate on which RCD's of the better quality range they were using for a nuisance issue tripping scenario. For the  love of me i cannot find the thread, but do recall someone referring to an ABB 2 pole type A RCD?  some guidance please as all of a sudden i have an intermittent nuisance tripping issue....thanks in advance

It's a 12-page thread with lots of stuff in it. Basically I spent way more money than I should have and researched the cr*p out of this one, narrowed it down to two appliances, one of which had a surge arrestor in it so simple (varistors to earth) that I knew this problem will be coming back again and again... so I took the plunge and installed a really expensive RCD. Which seems to be impossible to find anywhere other than RS components.

The fun starts around here on page 4.

19 hours ago, plonkster said:

It's a 12-page thread with lots of stuff in it. Basically I spent way more money than I should have and researched the cr*p out of this one, narrowed it down to two appliances, one of which had a surge arrestor in it so simple (varistors to earth) that I knew this problem will be coming back again and again... so I took the plunge and installed a really expensive RCD. Which seems to be impossible to find anywhere other than RS components.

One of the reasons for not being able to find a 30mA device that can handle DC currents is that CBI has a patent in SA for RCBO devices. So the manufacturers will not bring it in to avoid hefty penalties. The 100mA, 300mA and 500mA units on the other hand are free for all.

26 minutes ago, anotherbrownbear said:

CBI has a patent in SA for RCBO devices

O my @(#$*%$&!!! 

Translated that means You are going to pay more.

27 minutes ago, anotherbrownbear said:

100mA

I presume using a 100mA is not going to fly with regulations, for the patent is causing pain ito price for a 30mA.

5 minutes ago, The Terrible Triplett said:

O my @(#$*%$&!!! 

Translated that means You are going to pay more.

I presume using a 100mA is not going to fly with regulations, for the patent is causing pain ito price for a 30mA.

Depends on what you are using it for. If it is for macine protection, you can use higher ratings and this is normally specified by the inverter manufacturer. If it is to be installed on your socket outlets, then you are not allowed to se more than 30mA devices.

16 minutes ago, anotherbrownbear said:

socket outlets

Sockets ... any suggestions on make and model for a 30mA breaker that is not "overly sensitive", that does not cost +-R4k? :-) 

7 minutes ago, The Terrible Triplett said:

Sockets ... any suggestions on make and model for a 30mA breaker that is not "overly sensitive", that does not cost +-R4k? 🙂

Do you have only one RCD? Using mulitple RCD units in series also cause nuisance tripping. Have not found this using ABB though

Like @plonkster also mentioned, check your appliances for the guilty party. Maybe there is a SPD on one of your plugs or devices, those things are more of a nuisance than anything else. 

 

2 minutes ago, anotherbrownbear said:

... check your appliances for the guilty party.

I have a NE bondig issue, which is being handled - IF that solves the issue, then I am fine.

Asking for if that does NOT solve it. 

Plonkster and I also say that if it happened now, it can happen again when one buys a new thing in the future and plug it in. 

Over and above Surge Protection Devices, the problem also stems from SABS not testing it all anymore so we are flooded with goods causing the general problem, Multigrid / Multiplus II just the last straw pushing it all over.

Part that intrigues me, we both have the same device, 50km apart, having the same problem ... what are the chances of that?

13 minutes ago, The Terrible Triplett said:

I have a NE bondig issue, which is being handled - IF that solves the issue, then I am fine.

Asking for if that does NOT solve it. 

Plonkster and I also say that if it happened now, it can happen again when one buys a new thing in the future and plug it in. 

Over and above Surge Protection Devices, the problem also stems from SABS not testing it all anymore so we are flooded with goods causing the general problem, Multigrid / Multiplus II just the last straw pushing it all over.

Part that intrigues me, we both have the same device, 50km apart, having the same problem ... what are the chances of that?

I think your NE bonding issue will sort it out when sorted. Hold off on buying equipment that isn`t necessarily required. 

1 hour ago, anotherbrownbear said:

check your appliances for the guilty party

I narrowed it down to three appliances. For one I ripped out the EMI device, which I deemed unnecessary (low frequency power supply design). The trouble was that of the remaining two, each one on their own was enough to trip the RCD. So even if I split it right down to one appliance per RCD it would still nuisance trip in two places every time. That was when I realised I cannot fix this problem with more splitting.

The device I installed is not an RCBO (ie it has no overload protection), so it should not run foul of the CBI patent.

Regarding finding intermittent earth faults in general:

I know, or put it this way, I actually don't know how much electrical fault finding experience people have on this board.

So, at the risk of stating something that many will take for granted, this is where a megger beats a multimeter.

3 minutes ago, phil.g00 said:

Regarding finding intermittent earth faults in general:

I know, or put it this way, I actually don't know how much electrical fault finding experience people have on this board.

So, at the risk of stating something that many will take for granted, this is where a megger beats a multimeter.

An insulation resitance tester is quite handy when using it for just that.. When it comes to doing more serious tests, you need something bigger. Helermanntyton actually sells a HT Italia tester that can all of the above. It can do the whole compliance test, right down to the last little voltage measurement that you require.

27 minutes ago, anotherbrownbear said:

HT Italia tester

A very broad product range, very fancy, what model would you suggest is within a mere mortal's budget, with a mind to do pre-compliance checks?