DONT RELY ON RCD's PLEEEEESE.

[GLENNSPARK]

Yes, I remember.



Talking about working at heights, I'm doing a job next week where I've got a 50ft boom arm cherry picker. I need someone I can trust on the ground to operate the dead mans switch if needed, and also to get the bloody general public away from where we are working. Do you fancy it at a decent rate? Up to you Glenn.



We may have had a falling out on here in the past, but Glenn is someone I can trust on site. You are more than welcome to "get my back" in a difficult working environment.

No wheely bins are involved pmsl. (was it a black bin or a recycle bin lol).

sorry Paul...
but i`m busy these days....

theres a young 17 year old lad that comes out with us...he`s good for watching backs...
i`ll have a word with him...if you like...

 

[Paul.M]

sorry Paul...
but i`m busy these days....

theres a young 17 year old lad that comes out with us...he`s good for watching backs...
i`ll have a word with him...if you like...

A seventeen year watching my back? I dont think so mate. Dont care how good he thinks he is.

If you cant do it, I'll get someone else that I can trust.

 

[efficiencyman]

I have clicked on the "like" button for the comments I agree with. In the 53+ years since my electricians apprenticeship and become a qualified lion tamer, I too would uphold this rant for safety`s sake. I have been called to an electrocuted chap, to isolate the supply and make safe for the ambulance crew. Most unfortunate for all concerned, especially wife & 4 young kids, Although it was before RCD`s were introduced, the reliance on such devices must not be taken for granted as with the OP in this thread. I have all to often come accross DIY & immigrant bodge ups of appaling wiring ---- --- cant write it there were no standards let alone common sense.
Also periodic tests of RCD`s & full EICR test reports are vital to safe guard your own reputation & legal obligations.
Another comment, I have come accross several faulty (not tripping at correct rating ) RCD`s which must be EICR reported & notified for urgent replacement. How many of these were fitted without being tested I have often wondered. Profesionalism in our trade is essential, Sadly those days are on the decline, any hint of "cowboy" slap dash for cash must be stamped out. Many on here like to help people, DIY`ers and learners please be compliant & have your work certified or better still have the done by a professional in the first place.

 

[telectrix]

hope you're not going to attempt this until after the storm warnings are over. @50ft. the wind will be awesome.

 

[telectrix]

where's my cherry picker gone?

 

[Engineer54]

Originally Posted by Engineer54
Actually the 30mA RCD value is a compromise between safety and nuisance tripping that Europe has basically adopted for socket outlets and the like. We use 10mA for many of our outlet circuits within the hospital buildings, as the sick, the very young and older people are far more susceptible to shock risks than a typical healthy body... Even 10mA RCD's are no guarantee against receiving a fatal shock....

It's far too common for today's sparks to think of RCD devices as cure all devices especially to overcome severely deficient Zs values!! They don't ever seem to think of what happens when and if an RCD fails, which by the way, is far more often than most will imagine!!! In case you have forgotten,you were recently falling over yourself to congratulate an Ra of 15 ohms,which in my world is totally reliant on an RCD to disconnect an earth fault.


The crux of this thread, is the often proclaimed view that RCD's protect against electric shock, which we all know(or should know) they Do Not, they only limit the time a person is in direct, or indirect contact with the fault. They Do Not limit current as such (which is why you test at both rated value and at 5X rated value). So if electricians are going round telling customers that RCD's will protect them from electric shock, it is ''THEY'' that are Wrong!!!

I didn't fall over myself, that was just YOU me old cocker, trying to be clever ....as always!! Perhaps you have forgotten that i have always proclaimed my inherent distrust of relying totally on a RCD device, especially on TT systems. I have never however, stated that they are totally useless, they do serve a very useful purpose, but only when they are working perfectly!! They are just not at this time, particularly reliable devices....

 

[silverfox1]

Out of interest....all you guys that carry out EICR ......how many RCD's do you fail as they do not operate within time limits or not at all. I was told recently that 7% RCD's fail! Not good if you are receiving a shock.

Mmmm so 93% of RCDs pass , agree though would not be nice to be on the end of one of the 7%.

 

[Jibapproved]

Think some of these guys have been sold the wrong application of the use of a rcd. There is indeed a risk of electric shock as there is on any energised circuit but where rcds are installed there dosnt appear to be any recorded deaths but there must be thousands of shocks due to direct contact due to idiots leaving live plate switches hanging off the wall

 

[baldsparkies]

The thread has received a good response and I just hope that any sparkies who have been telling Joe public that an RCD protects them from electric shock will now think before making such comments.
As said in some comments they are like an airbag. But if you hit a wall at 100 mph, game over.
An RCD can assist in electrical safety under certain fault conditions, nothing more, nothing less. Now Im 60 years old, this is one old electrician who will not be relying on them to save my life.

 

[Paul.M]

hope you're not going to attempt this until after the storm warnings are over. @50ft. the wind will be awesome.

I suppose to be starting this Monday (tomorrow) but they forecast 80mph gusts! Think I'll leave it for Wednesday or Thursday and see what the weather is like lol.

Ironic really, me and the customer are in the hands of the Gods, and its a place of worship. All work needs to be completed by the 2/11 so time is against us.

Thread back on track. Yes my circuits will be on RCBO's and I wont tell them that they a miracle cure for incompetence or have a go Joes to play with.

 

[UNG]

Back in my days at college I was always taught that RCD's or ELCB's as they were then should be treated and used as secondary forms of protection and not as a substitute for proper circuit design

How many people (customers) actually follow the instructions to press the test button every 3 months to check the RCD functions, over the years I have come across many RCD's that are stuck and don't trip when the test button is pressed or a tester is used so how much reliance can you put on it operating when required. May be there is a market for an RCD with a timer built in to warn it needs testing every 3 months

We all know that a fuse is a single use device but we have no idea how many times an MCB or RCD has been tripped by faults and how it's reliability and calibration has been affected by this and other factors like ageing (springs weakening etc)

Statistics are used a lot but there is no way to collect data on the number of lives that have been saved due to RCD's as an RCD tripping is never reported but you never hear of any stats or incidents where RCD's have failed to operate causing a fatality or serious injury a few have already admitted on here that they avoided serious injury due to RCD's and I think if most of us are honest we all have had similar experiences and will never know whether the overcurrent device would have cleared quick enough to save us

 

[Deleted member 9648]

I attended the aftermath of a DIY death where the deceased was in contact with a live cable under the floor while kneeling against an earthed water pipe running through the same joist.....he literally cooked before someone hit the main switch.I have no doubt whatsoever that had an RCD been in circuit it would have tripped instantaneously and probably saved his life.

 

[GLENNSPARK]

Back in my days at college I was always taught that RCD's or ELCB's as they were then should be treated and used as secondary forms of protection and not as a substitute for proper circuit design

How many people (customers) actually follow the instructions to press the test button every 3 months to check the RCD functions, over the years I have come across many RCD's that are stuck and don't trip when the test button is pressed or a tester is used so how much reliance can you put on it operating when required. May be there is a market for an RCD with a timer built in to warn it needs testing every 3 months

We all know that a fuse is a single use device but we have no idea how many times an MCB or RCD has been tripped by faults and how it's reliability and calibration has been affected by this and other factors like ageing (springs weakening etc)

Statistics are used a lot but there is no way to collect data on the number of lives that have been saved due to RCD's as an RCD tripping is never reported but you never hear of any stats or incidents where RCD's have failed to operate causing a fatality or serious injury a few have already admitted on here that they avoided serious injury due to RCD's and I think if most of us are honest we all have had similar experiences and will never know whether the overcurrent device would have cleared quick enough to save us

and on TN arrangements RCDs/RCBOs are refered to as `additional protection`...

 

[GLENNSPARK]

I suppose to be starting this Monday (tomorrow) but they forecast 80mph gusts! Think I'll leave it for Wednesday or Thursday and see what the weather is like lol.

Ironic really, me and the customer are in the hands of the Gods, and its a place of worship. All work needs to be completed by the 2/11 so time is against us.

Thread back on track. Yes my circuits will be on RCBO's and I wont tell them that they a miracle cure for incompetence or have a go Joes to play with.

so...does this mean you will neglect to inform the client about the importance of testing quarterly (i advise every month) Paul...?

 

[Marvo]

Even the testing methods of RCD's is problematic in my book. It's common practice to operate the unit several times before taking the test readings because it's highly likely to fail the tests if you don't. This certainly doesn't happen in real life when someone gets a shock and gives a skewed picture of how effective the device may be at saving a life.

 

[Engineer54]

Out of interest....all you guys that carry out EICR ......how many RCD's do you fail as they do not operate within time limits or not at all. I was told recently that 7% RCD's fail! Not good if you are receiving a shock.

Who come up with this random figure of 7%?? I fear it's a much higher figure than that, going by Actual experience from previous projects, and nothing seems to have changed on my present project either!!

 

[Marvo]

To be honest 7% sounds high. I just looked at our product failure records and out of 166 RCD's over 4 years we had 4 faulty from new that didn't make it past the test bench and 2 failures in service. All these RCD's were used in panels we built. I don't have records available for miscellaneous installed and replaced units on other sites and installations.

 

[Aindowsimon]

what people should remember as well is even though RCDs have ommitted the need for crossbonding of boilers it would be wise to do so....
call it backup...

Cross bonding under a boiler is a waste of time ( definitely on Worcester ones ) as all relevant pipe work ar connected to a manifold in boiler joined together on a steel plate as pictured I'm sure this is the case with most boiler manufacturers .

But I do admit I'm with you on you're underlining sentiment cross bonding. having as much installation exposed metal work at equal potential is a good way to work and only makes places/installations safer .

 

[Englishman]

Out of interest....all you guys that carry out EICR ......how many RCD's do you fail as they do not operate within time limits or not at all. I was told recently that 7% RCD's fail! Not good if you are receiving a shock.

I've only had one fail from the last 100 or so that I've tested.

As for them failing when you hit the test button, new rcds and rcbos routinely fail to trip until you've tested them a few times.

 

[Engineer54]

To be honest 7% sounds high. I just looked at our product failure records and out of 166 RCD's over 4 years we had 4 faulty from new that didn't make it past the test bench and 2 failures in service. All these RCD's were used in panels we built. I don't have records available for miscellaneous installed and replaced units on other sites and installations.

Numbers only become noticeably apparent, when you are looking at literary several hundred or thousands of RCD units of all types and descriptions on the larger projects. As i've stated a few times now, the contractors on these projects was sending boxes of the things back to the manufacturer (and were not talking about a budget manufacturer but top end one) on a pretty regular basis for replacement. Id go as far as saying that the figures were more like 12 to 15% overall....