Does a boat need PAT Testing

[GUMPY]

Fine until something goes wrong and someone gets injured!

[Alan de Enfield]

14 minutes ago, Loddon said:

Fine until something goes wrong and someone gets injured!

Completely agree.

 

But the PAT testing (just like the boat BSSC, or the Car MOT) doesn't stop you changing/amending things  (fuses, extending the cable, re-termination etc etc.)

It is only 'good' whilst the tester is on site.

 

I paid external inspectors to come and stick labels on our plugs (and paid about £1 per plug for the service) , but I could have quite easily done it myself.

Its crazy when 'important' things like fire certificates, (numbers allowed in buildings) fire inspections, numbers of extinguishers etc have been done away with and you now self-certify.

 

I had to write my own risk assessment for 'chance of fire and severity & impact of fire' for each area of the business (Kitchens, changing rooms, bar etc) and identify how risk could be minimised (removal of waste paper etc). Surely things like that are better left to professionals ?

[LadyG]

47 minutes ago, Alan de Enfield said:

Completely agree.

 

But the PAT testing (just like the boat BSSC, or the Car MOT) doesn't stop you changing/amending things  (fuses, extending the cable, re-termination etc etc.)

It is only 'good' whilst the tester is on site.

 

I paid external inspectors to come and stick labels on our plugs (and paid about £1 per plug for the service) , but I could have quite easily done it myself.

Its crazy when 'important' things like fire certificates, (numbers allowed in buildings) fire inspections, numbers of extinguishers etc have been done away with and you now self-certify.

 

I had to write my own risk assessment for 'chance of fire and severity & impact of fire' for each area of the business (Kitchens, changing rooms, bar etc) and identify how risk could be minimised (removal of waste paper etc). Surely things like that are better left to professionals ?

Like the electrician who was asked to blank off my cooker while we did kitchen renovations. He rocked up, a day late, switched the oven off at the wall, and proceeded to cover the end of the power cable with earthing type sticky tape. It was left like that.

Meantime I went to the main power source and turned off the mains electricity. The other workman told me I was over-reacting as the electrician "knew" what he was doing. The evidence denies that, and he never came back. Might just have been because I mentioned I used to sign off works for grant aid, I genuinely needed to know how he intended to extend the electrical system, but he wasn't happy to explain anything. 

The one who eventually did some work managed to instal a faulty 30amp switch and a wall switch non compatible with the lighting system, he refused to return unless I paid him again. I will have to do it myself!

Edited February 18, 2019 by LadyG

[Momac]

54 minutes ago, Loddon said:

 

 

Could be an interesting conversation with HSE if a computer/extension lead developed a fault and electrocuted someone.

 

 

Yes it would.

 

 

[LadyG]

10 minutes ago, MartynG said:

Yes it would.

 

 

According to my Local Authority "Inspector", if I have an accident at my business premises I should call them [the LA] out. , I knew this advice to be inaccurate, and said so, absolute idiots.

Edited February 18, 2019 by LadyG

[Horace42]

When you attend your training course, (and assuming you have your own PAT tester), then in this scenario, you would be the 'expert' and thus would be able to tell us we need our boat tested, or not.

I am curious about the content of the training course and why it is necessary. Let's face it, you can buy a PAT tester off Amazon or eBay, read the instructions, and become a 'Tester'.

So does the course cover more details like electrical theory, form filling etc, (that creates an audit trail of responsibility when you issue 'pass' certificates), and how to service the actual equipment you will be testing, and perhaps more importantly how to find and 'fix' faults.

Having read the replies to date, I would be inclined to say boats are exempt. But having said that it would be so easy to plug a boat into your PAT - and interesting to see what happens.

 

[1st ade]

41 minutes ago, Horace42 said:

I am curious about the content of the training course and why it is necessary. Let's face it, you can buy a PAT tester off Amazon or eBay, read the instructions, and become a 'Tester'.

So does the course cover more details like electrical theory, form filling etc, (that creates an audit trail of responsibility when you issue 'pass' certificates), and how to service the actual equipment you will be testing, and perhaps more importantly how to find and 'fix' faults.

I don't know and that's why I'm going to do it. I initially went down the "buy one and read the book", then thought (as others have mentioned) what if there's an accident? To take the example of the wall mounted TV in a charity shop, I'm putting my name and other details to a system which could kill a member of the public; albeit under a somewhat bizarre set of circumstances.

I'm much happier replying "look, here's my training certificate, here's the calibration certificate for the PAT Tester and here's the form i completed on site" when the midden hits the windmill. (And yes, I know it's only really valid on the day but a completed certificate is better than no certificate when the enquiry finds a nail across the fuse holder. No certificate = I couldn't be bothered to check; certificate = I deliberately falsified the inspection or someone tampered after I left)

41 minutes ago, Horace42 said:

Having read the replies to date, I would be inclined to say boats are exempt. But having said that it would be so easy to plug a boat into your PAT - and interesting to see what happens.

 

So what will a PAT Test do to a Galvanic Isolator?

[Machpoint005]

20 hours ago, zenataomm said:

I guess it is relevant for boats,

 

Only if the boat is a place of work.

[Momac]

In addition to the test a visual inspection should be carried out since the test may not necessarily reveal  a physical defect.

 

 

 

 

 

 

[GUMPY]

1 hour ago, MartynG said:

In addition to the test a visual inspection should be carried out since the test may not necessarily reveal  a physical defect.

 

Indeed it wont.

You can test a 16amp cable that only has 3 or 4 strands of each core connected and it will pass! I did this years ago when I was told that a visual inspection didn't matter and it was all about the test.

However a visual inspection will if done fully pick this up.

A boat with a GI will fail on the earth resistance test, however depending on the settings of the tester it should survive.

As for the IR test it should survive that as well.

When I was involved with testing on a regular basis I used to put "duff" cables into the pile just to see if the testers picked them up, if they didn't then I wanted to know why.

 

ETA

Testing is just an ass covering exercise, you have to be able to prove that your equipment is electrically safe in the case of an accident and PAT has become the accepted way.

You could equally have a meticulous inspection record which may also stand up in court depending on the item.

 

Edited February 18, 2019 by Loddon

[GUMPY]

Just found this website that deals with a lot of electrical testing

Only looked a a couple of bits but seems well explained an thorough.

If you have an interest in testing etc only go there if you have lots of bandwidth and an afternoon to spare

https://www.flameport.com

[1st ade]

36 minutes ago, Loddon said:

...I used to put "duff" cables into the pile just to see if the testers picked them up, if they didn't then I wanted to know why

"Greenie"

[Horace42]

11 hours ago, 1st ade said:

I don't know and that's why I'm going to do it. I initially went down the "buy one and read the book", then thought (as others have mentioned) what if there's an accident? To take the example of the wall mounted TV in a charity shop, I'm putting my name and other details to a system which could kill a member of the public; albeit under a somewhat bizarre set of circumstances.

I'm much happier replying "look, here's my training certificate, here's the calibration certificate for the PAT Tester and here's the form i completed on site" when the midden hits the windmill. (And yes, I know it's only really valid on the day but a completed certificate is better than no certificate when the enquiry finds a nail across the fuse holder. No certificate = I couldn't be bothered to check; certificate = I deliberately falsified the inspection or someone tampered after I left)

So what will a PAT Test do to a Galvanic Isolator?

I don't know what it will do to a Galvanic Isolator, GI, or vice versa - I don't know what is 'inside' a PAT tester - but I vaguely recall a simple boat type GI is nothing more than a couple of power diodes connected in the earth wire. The experts will be able to tell you.

I am sure you are doing the right thing by going on a training course and it will be a good thing - all part of the audit trail if things go wrong.

[Boater Sam]

GI is two pairs of silicon diodes in series inverse parallel.

Either series pair will conduct on alternate half cycles of the mains input if there is leakage to the earth connection. This allows up to 1.3v across the diodes before they conduct and take out the RCD. So you can still have 1.3v of galvanic corrosion voltage on the hull with respect to true earth.

[1st ade]

6 hours ago, Boater Sam said:

So you can still have 1.3v of galvanic corrosion voltage on the hull with respect to true earth.

I thought the idea was it removed 1.3 volts from any galvanic potential difference? so if my boat (relative to the shore) is half a volt positive then zero current will flow (and hence zero corrosion) but if I have a fault to mains then enough current will flow to trip the breaker.

 

I stand by to be corrected - I'm not a marine electrician!

[Boater Sam]

Its a possible potential only. The corrosion question is even more complicated by the fact that mains is AC so it should return any metal every half cycle.

DC or course will make your boat either the anode or cathode depending on the polarity. This has relevance and is why cars are negative ground and non isolated boats also.

 

I'm not a marine electrician either, I started in the missile days!

[Tony Brooks]

7 hours ago, Boater Sam said:

GI is two pairs of silicon diodes in series inverse parallel.

Either series pair will conduct on alternate half cycles of the mains input if there is leakage to the earth connection. This allows up to 1.3v across the diodes before they conduct and take out the RCD. So you can still have 1.3v of galvanic corrosion voltage on the hull with respect to true earth.

I think some GIs now use three diodes in series because the increasing use of switched mode power supplies tend to put higher voltages on the "earth" wire from radio interference suppression.

 

Th idea is that the forward bias voltage of the diode before it conducts will block any  likely voltage on the "earth" cable whilst allowing the very much higher fault voltages to flow (OK I know its current). I don't see how you can have any corrosion voltage on the hull until the required forward bias voltage of the diodes is reached.

 

Also not a marine electrician but motor industry trained.

[cuthound]

16 minutes ago, Tony Brooks said:

I think some GIs now use three diodes in series because the increasing use of switched mode power supplies tend to put higher voltages on the "earth" wire from radio interference suppression.

 

Th idea is that the forward bias voltage of the diode before it conducts will block any  likely voltage on the "earth" cable whilst allowing the very much higher fault voltages to flow (OK I know its current). I don't see how you can have any corrosion voltage on the hull until the required forward bias voltage of the diodes is reached.

 

Also not a marine electrician but motor industry trained.

 

This is exactly how they work, plus some have a capacitor connected across the diodes to shunt the low current but high frequency ripple caused by switch mode power supplies to earth., because it is the DC current that causes the electrolytic corrosion.

 

Also not a marine engineer, but I spent a career in critical power engineering and have qualifications in industrial electronics and power engineering.

[Boater Sam]

I explained badly, the diodes produce a hold off voltage equal to their forward breakdown voltage so that the current is zero until that voltage is exceeded.

It is of course the current not the voltage that causes the electrolytic corrosion.

I have never fully understood whether a shunt capacitor compromises the diodes to some extent.

Mine is two  40A bridge rectifiers connected back to back, 2 junctions only in series. Interesting to hear that now some are 3 junctions giving around 1.8 v hold off.

[Horace42]

51 minutes ago, Boater Sam said:

I explained badly, the diodes produce a hold off voltage equal to their forward breakdown voltage so that the current is zero until that voltage is exceeded.

It is of course the current not the voltage that causes the electrolytic corrosion.

I have never fully understood whether a shunt capacitor compromises the diodes to some extent.

Mine is two  40A bridge rectifiers connected back to back, 2 junctions only in series. Interesting to hear that now some are 3 junctions giving around 1.8 v hold off.

Very much the same as mine. When called 'bridge rectifiers' you can make your own basic unit for circa £10. When bought  ready made and sealed in a box and called 'galvanic isolators' they are circa £80 - £150 depending on the 'extras'

 

[Chewbacka]

3 hours ago, Horace42 said:

Very much the same as mine. When called 'bridge rectifiers' you can make your own basic unit for circa £10. When bought  ready made and sealed in a box and called 'galvanic isolators' they are circa £80 - £150 depending on the 'extras'

 

Not wishing to stir up an older thread, but will your home made isolator withstand a peak current of over a thousand amps for a few mS or have adequate heatsinking to withstand 16A indefinitely?  Though the need to withstand 16A does assume either the rcd device is missing or not working, so less likely to be a worry today.

[Horace42]

1 hour ago, Chewbacka said:

Not wishing to stir up an older thread, but will your home made isolator withstand a peak current of over a thousand amps for a few mS or have adequate heatsinking to withstand 16A indefinitely?  Though the need to withstand 16A does assume either the rcd device is missing or not working, so less likely to be a worry today.

I fitted mine to counter milliamp stray leakage because my boat is seldom used and moored at home and permanently plugged in to mains.

I haven't the faintest idea of the fault current capabilities of my cheap GI. ... but you have got me thinking ...

When I have a moment I will dust off my multi-tester and check-out the whole boat installation and RCD tripping times...thanks for the tip..... and useful to think about if anybody wants to make their own...

[GUMPY]

41 minutes ago, Horace42 said:

I fitted mine to counter milliamp stray leakage because my boat is seldom used and moored at home and permanently plugged in to mains.

 

I haven't bothered with a GI despite my boat spending most of its time connected to shore power.

 

 

 

 

 

 

 

 

 

 

 

 

I fitted the first Airlink Isolating transformer back in 2006. Much safer and more reliable.

[rusty69]

3 minutes ago, Loddon said:

fitted the first Airlink Isolating transformer back in 2006. Much safer and more reliable.

First one? Did it fail then?

[GUMPY]

57 minutes ago, rusty69 said:

First one? Did it fail then?

No, I approached Airlink in 2006 and suggested they built an Isolating transformer in a plastic case for boats.

Mine was in fact a bare transformer as a test, now housed in a custom HDPE case.