Priority Switch Problems

Xwebstar2 wrote: »

By the way I'm not disputing that Rcbos give trouble

My issue is with the blanket type of statement you're making above

I don’t think Sleeper has made a “blanket statement”. I believe that he is simply sharing his knowledge based on a wealth of experience in a particular area. I suspect that nobody else on this forum has dealt with half as many electrical shower issues as him.

I also see that he is fully compliant in terms of restricted work, he uses a REC when required.

Sleeper12 wrote: »

. I have seen a shower needing the RCBO replaced three or even four times before everything settles down. I have seen a brand new RCBO trip on a shower & have to be replaced. The same RCBO could then work perfectly with another shower of the exact same make & model.

This would suggest to me that the Rcbos are not being tested, merely replaced as a quick fix

How can an Rcbo possibly be needing to be replaced 4 times to "settle down?" if it is tested after replacement

Xwebstar2 wrote: »

This would suggest to me that the Rcbos are not being tested, merely replaced as a quick fix

Wouldn’t you expect the REC to test the RCBOs?

Modern elements don't really leak any more due to improvements in design. Modern Pumped electric showers have low voltage motors. The only part in the shower with earth connected to it is the element. If someone tells me over the phone that the shower is tripping intermittently I ask has anyone literally held the shower head over the shower running water over it. If the answer is no then I don't go out. I send a REC. I know that the issue is most likely to be the RCBO. Less often its the pull cord switch in this particular situation. It's even possible to be a damaged cable but almost always it is the RCBO. I know this without ever visiting the home. If I'm wrong I'd have to pay REC for wasted visit. This doesn't happen though.

Had a call from a lady in a council house two weeks ago. Shower was intermittently tripping. I said it's not the shower, it's likely to be the RCBO. She said no, the council sent out a REC & he already replaced the RCBO. I told her that he needs to change it again. He wouldn't come back because he put in a new RCBO so it has to be the shower. I sent my REC out to replace the new RCBO. Shower hasn't tripped since. It doesn't happen often but I don't lie when I say I've seen the RCBO needing replacing several times

Sleeper12 wrote: »

Modern elements don't really leak any more due to improvements in design. Modern Pumped electric showers have low voltage motors. The only part in the shower with earth connected to it is the element. If someone tells me over the phone that the shower is tripping intermittently I ask has anyone literally held the shower head over the shower running water over it. If the answer is no then I don't go out. I send a REC. I know that the issue is most likely to be the RCBO. Less often its the pull cord switch in this particular situation. It's even possible to be a damaged cable but almost always it is the RCBO. I know this without ever visiting the home. If I'm wrong I'd have to pay REC for wasted visit. This doesn't happen though.

Had a call from a lady in a council house two weeks ago. Shower was intermittently tripping. I said it's not the shower, it's likely to be the RCBO. She said no, the council sent out a REC & he already replaced the RCBO. I told her that he needs to change it again. He wouldn't come back because he put in a new RCBO so it has to be the shower. I sent my REC out to replace the new RCBO. Shower hasn't tripped since. It doesn't happen often but I don't lie when I say I've seen the RCBO needing replacing several times

Shower trips Rcbo

Council change Rcbo

Rcbo still tripping

Send your rec to replace Rcbo again

Xwebstar2 wrote: »

Shower trips Rcbo

Council change Rcbo
REC does not bother testing replacement RCBO

Rcbo still tripping

Send your rec to replace Rcbo again
This replacement RCBO is ok

Perhaps what I added in bold is correct? It would be quite unlucky but it is possible.

Personally I have not seen many faulty RCBOs but I have come across them.

2011 wrote: »

Perhaps what I added in bold is correct? It would be quite unlucky but it is possible.

Personally I have not seen many faulty RCBOs but I have come across them.

Could be the case here

However this is not a standard methodology when troubleshooting

Xwebstar2 wrote: »

Could be the case here

I would suspect so.

However this is not a standard methodology when troubleshooting

We don’t know what methodology Sleeper’s REC used.
Whatever he did it appears to have worked.
I think we should give him the benefit of doubt.

Xwebstar2 wrote:

Send your rec to replace Rcbo again

And the shower repair company did what DCCs electrician couldn't or wouldn't do. DCCs electrician couldn't fix the problem because he had tunnel vision. He'd never come across a new faulty RCBO before. He blamed the shower, walked away and wouldn't come back. Because we see this problem very regularly we were able to fix it.

I deliberately didn't quote or tag you in my comment because this back & forward is going nowhere. You are flogging a dead horse here.

Risteard81

The fact is that it is very rare for the RCD to be at fault in spite of the many (spurious) claims.

Risteard81 wrote: »

The fact is that it is very rare for the RCD to be at fault in spite of the many (spurious) claims.

I'm investigating RCD issues for as long as I can remember, circa 30 yrs

I'm amazed to hear that a faulty Rcbo is the cause of the majority of intermittent faults

If this was the case RECs would need a constant supply of RCBOS and RCDs for replacement of same

Risteard81 wrote:

The fact is that it is very rare for the RCD to be at fault in spite of the many (spurious) claims.

How many showers do you repair in a year that you base that statement on? How many showers in your life time?

Risteard81

Sleeper12 wrote: »

How many showers do you repair in a year that you base that statement on? How many showers in your life time?

I base the statement on fact and good engineering judgment.

It is of course possible for RCDs to fail, but it is the least probable outcome when diagnosing tripping.

Off the top of my head the majority of RCD/Rcbo issues ime

1) RCD not passing all trip tests when fitted new

2) " Stiction "from test button not being pressed or RCD not tripping at all

3) Overload, loose connections or rcd contacts causing burnout at RCD

4) misc wiring faults/issues downstream causing tripping

I'm not aware of this phenomenon of over-sensitive Rcbos requiring replacement in the majority of cases of intermittent faults.

Risteard81 wrote:

It is of course possible for RCDs to fail, but it is the least probable outcome when diagnosing tripping.

With the shower ruled out due to it being intermittent tripping that leaves pull cord switch damaged cable or RCBO. Statistically it is much more likely to be the RCBO compared to the pull cord switch or damage cable. More times than not the pull cord switch will trip instantly.

Xwebstar2 wrote:

I'm not aware of this phenomenon of over-sensitive Rcbos requiring replacement in the majority of cases of intermittent faults.

Other electricians here have already said that they come across them ofter enough. We're not all telling lies you know

Off topic but something that I can't recall coming across before happened this morning.

Before we touch a shower we check live neutral voltage and live earth voltage. Often with power showers we'll find bad earth readings. Id almost never get a bad earth reading on an electric shower. This morning (first time ever for me as far as I remember) I got a L N of 239v making the 9kw shower closer to a 10kw but the Earth had a reading of one. I'm sure many here can tell me I don't get out enough & that this is common but I pretty sure I haven't seen such a reading on an electric shower before. Like the News of the world reporter "I made my excuses and left". It'll have to be made safe before I can return to it.

239v would be highly unusual

I don't think that there is any benefit to keeping this thread open any longer, it is just going around in circles.

A few things to consider:

Many domestic electricians spend an entire career during which they work almost exclusively on wiring new installations. Assuming they are good at what they do then troubleshooting could be something they rarely have to do. All the equipment they install is new so is less prone to failure. Many industrial electricians could spend years without installing any RCDs or RCBOs.

Both of the above types of electrician may be highly skilled and very experienced but may never (or rarely) come across a faulty RCD or RCBO. I am in this game a long time and I can only remember 2 (off the top of my head).

I am going to guess that the above applies to both Xwebstar2 and Risteard81. If so they have probably dealt with less faulty showers in their entire career than Sleeper12 has dealt with in the last month. The obvious reluctance to put a number on how many tells its own story.

Then we have a poster that works in a business in which they only get a call if there is an issue with a shower, which seems to be around 1000 such calls a year. These units are (or should) only be fed from RCDs / RCBOs in every case this is in stark contrast with many of the circuits that most electricians work with. As shower units are becoming less and less prone to failure and are frequently fed from old ELCBs / RCDs /RCBOs it increases the likelihood of encountering faults with these devices. I would also imagine that many of these devices were not tested properly in the first place.

If anyone has anything new or constructive to add please PM me and I will unlock.

If the OP would like to respond with how things worked out I’m sure we would all be very interested. Obviously the thread could be reopened.

Mod note: Due to a number of requests by PM I will unlock the thread.

Debate is encouraged once it is civil.
Some interesting points have been made on both sides, so it would be best if we can avoid locking the thread or any other mod actions.

Thank you

Anyway, back on track

Xwebstar2 wrote: »

239v would be highly unusual

I think it is common enough to be honest. I have measured higher single phase voltages on various installations in Ireland.
Remember 230 volts is an average.

meercat

like to confirm from the op if the Car charger is on the same rcd as the showers as the op seems to think so in post 24.
I’d also like to know what happens if the test button is pressed on the rcd(does power switch off for showers and charger)(does the trip switch come down)cheers

Shefwedfan

meercat wrote: »

like to confirm from the op if the Car charger is on the same rcd as the shower as the op seems to think so in post 24.
I’d also like to know what happens if the test button is pressed on the rcd(does power switch off for showers and charger)(does the trip switch come down)cheers

The charger, shower x 2 are all into the same priority. After that I haven’t a clue.

All I know is when the fault happens it kills the power in one of the showers, the charger and other shower will still turn on

Push the button and it trips the switch down.

I’m no electrician, I do most handy work in house but plumbing and electrical are a step too far for me

meercat

Shefwedfan wrote: »

The charger, shower x 2 are all into the same priority. After that I haven’t a clue.

All I know is when the fault happens it kills the power in one of the showers, the charger and other shower will still turn on

Push the button and it trips the switch down.

I’m no electrician, I do most handy work in house but plumbing and electrical are a step too far for me

Can you clarify this one question
When the rcd is off, does it knock power off to all showers and the charger

Risteard81

2011 wrote: »

Anyway, back on track

I think it is common enough to be honest. I have measured higher single phase voltages on various installations in Ireland.
Remember 230 volts is an average.

230V is NOT an average - it is a nominal figure which is subject to tolerances. For example ESQCR in the UK states 230V +10%/-6% - there isn't an average of 230V. What happens is that it is transmitted at the upper end of the limit to allow for Volt drop keeping within the lower limit.

Risteard81 wrote: »

230V is NOT an average - it is a nominal figure which is subject to tolerances. For example ESQCR in the UK states 230V +10%/-6% - there isn't an average of 230V. What happens is that it is transmitted at the upper end of the limit to allow for Volt drop keeping within the lower limit.

Sounds about right

You are right, “average” was the wrong word.

Anyway that was not really my main point.
So you agree that 239 volts is not that unusual?

Xwebstar2 wrote:

239v would be highly unusual

I've come across plenty in the high 230s. When I say plenty I'd hazard a guess at 3 to 5 percent. A regular contributer in the plumbing forum has very close to 240v. I've found a higher percentage homes in the low 220s than the high 230s.

Funny everyone picked up on the 239v and no one has mentioned the electric shower with no reading on the earth. It's the first electric shower I've come across with no earth reading. Homeowner rang me this evening for anyone interested. REC inspected this afternoon and said they had a lucky escape. He's totally rewiring from fuse board to the shower. Black and red 6mm. Earth must be broken somewhere in the cable.

Shefwedfan

meercat wrote: »

Can you clarify this one question
When the rcd is off, does it knock power off to all showers and the charger

I would need to be 100% and check but no, just the one shower