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Topic Title: Compressor
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Created On: 05 January 2013 01:13 PM
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 05 January 2013 01:13 PM
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mrcornbeef

Posts: 245
Joined: 05 December 2005

Hi
On a job with a large compressor we have connected , we noticed inside the compressor the neutral had a solid link between it and earth , we have obviously provided separate conductors for both , it is a boge compressor is this link there for use in foreign country's ??
 05 January 2013 01:38 PM
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DOUGIE1000

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remove the link of course, that would not look good on your minor works certificate would it.

This was discussed recently regarding TN-C supies

-------------------------
Dougie
Power Plus Electrical.co.uk

My mission is to live as long as possible......so far so good!
 05 January 2013 02:10 PM
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mrcornbeef

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Yes removed link and informed commission engineer
just wondered why equipment for use in uk had it in ?
 05 January 2013 02:41 PM
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broadgage

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Originally posted by: mrcornbeef

Yes removed link and informed commission engineer

just wondered why equipment for use in uk had it in ?


I doubt that it is intended for UK use, no matter what the supplier may claim.
It probably uses a three phase motor that requires a protective earth but no neutral. Any 230 volt contactor coils or other controls would of course require a neutral.
In some countries it is common practice to connect contactor coils and lights on machine tools between one phase and earth, thereby saving the expense of a neutral wire.
Prohibited in the UK and most unwise IMHO even in countries that permit it.
 05 January 2013 07:02 PM
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perspicacious

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It was fairly common at one time to "derive" a neutral from the star point of a motor for associated ancillary low wattage equipment.....

Regards

BOD
 05 January 2013 08:26 PM
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slittle

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It was fairly common at one time to drown witches but I understand they've even banned that in your parts now Bod :-D

Stu
 05 January 2013 08:48 PM
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perspicacious

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Leominster Ducking Stool anyone?

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BAD
 05 January 2013 09:00 PM
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mrcornbeef

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Thanks for replies
another one for you guys off topic but here goes..
having been watching coronation street sorry being forced to watch by her in doors Tyrone has been fiddling with the boiler naughty !not gas safe and all that and gases poor fizz
Just thinking if us lot would get pulled in after doing electrical work on a boiler and something went wrong after us .i know when i work on a boiler there is heating engineer / plumber to final commission it, but what happens if a sparky disturbs something testing or putting a new cable in etc. should we have them tested after we have touched it for gas leaks and carbon monoxide
Just thinking aloud
 05 January 2013 09:11 PM
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perspicacious

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"Tyrone has been fiddling with the boiler naughty !"

I think I'd better let that one pass

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BED
 05 January 2013 09:28 PM
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Rulland

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Watch your butts people, because it can only get worse!
http://news.bbc.co.uk/1/shared..._pierjudgement247.pdf

30 million awarded.

-------------------------
Those who make no mistakes do very little work!!......
 05 January 2013 10:45 PM
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briandoherty

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Originally posted by: mrcornbeef
Just thinking if us lot would get pulled in after doing electrical work on a boiler and something went wrong after us .i know when i work on a boiler there is heating engineer / plumber to final commission it, but what happens if a sparky disturbs something testing or putting a new cable in etc. should we have them tested after we have touched it for gas leaks and carbon monoxide


As my post of 22/jan/10 (see http://www.theiet.org/forums/f...tid=205&threadid=34367);

Gas Safe Register Technical Bulletin 043, Electrical work on gas appliances, Issued 26 October 2009, states the following (underline emphasis is mine):

Introduction
Following correspondence between the Electrical Contractors Association (ECA) and the Health and Safety Executive (HSE) regarding electrical work that can be carried out on a gas appliance without a requirement for being registered with Gas Safe Register, the following statement has been issued by the ECA and has been "endorsed" by the HSE and the Electrical Safety Council (ESC).
Note:
"Where an electrical contractor is installing or maintaining electrical components of a gas system, e.g. solenoid valves, pumps, time switches, provided this work does not involve disconnection of a gas fitting, i.e. breaking into the gas path or combustion system, registration with Gas Safe Register is not necessary.
"

However, notwithstanding requirement for registration, any issues associated with work which affects the operation of gas appliances can result in prosecution under the Gas Safety (Installation and Use) Regulations; this typically happens when double glazing companies erect conservatories over existing flue terminals, etc. but could also apply where electrical work adversely affects gas appliance operation.

-------------------------
Regards,

Brian
 05 January 2013 11:03 PM
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DOUGIE1000

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I repair gas boilers, in fact replaced PCB in my own com I boiler at home this morning, as I don't touch gas vales, gas pipe gas meter etc I can work on boilers without problem (we sub out gas works and also more importantly flue works).

-------------------------
Dougie
Power Plus Electrical.co.uk

My mission is to live as long as possible......so far so good!
 06 January 2013 09:51 AM
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tomgunn

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Originally posted by: slittle

It was fairly common at one time to drown witches but I understand they've even banned that in your parts now Bod :-D



Stu




-------------------------
Tom .... ( The TERMINATOR ).

handyTRADESMAN ... haha

Castle Builders

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 06 January 2013 10:09 AM
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tomgunn

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Originally posted by: DOUGIE1000

I repair gas boilers, in fact replaced PCB in my own com I boiler at home this morning, as I don't touch gas vales, gas pipe gas meter etc I can work on boilers without problem (we sub out gas works and also more importantly flue works).


I have always installed boilers for clients and myself - its all legal as I run the gas main and fix the boilers but leave the flue ready to be installed by the gas man as it has to be installed, or checked, by them. I leave the gas supply next to the gas mains and all they have to do is to connect it... simple a/ Nah - exactly this time last year I installed a new gas hob in my own kitchen here - I bent / double set the new copper pipework - set the gas hob into the new worktop - and all these gas people, that I use to connect the gas items, was to screw the join on to the gas hob, ( I had to have a cert as for one I have sold my house and also I like to do things properly also a worrier too !), - and thats it! They came - connected the pipe to the hob - so I started to fix in the draws and smelt gas! I got some washing up liquid - mixed a bit of water with it - painted it around the only joint that they connected and what do you think? It was leaking! I called them and he said that he had just started to decorate his front room and he would come round the next morning!! What a service - happy to leave a job for some 24 hours with a gas leak! Haha - woulda been safer if I had done it and carried out a pressure check myself!

When I woz a lad - probably my first week as an apprentice sparks, ( 1967 a?! ), one of my foremen gave some advice that still sticks to this day - Tommy Church said to me... 'remember this - if you don't do it, ( referring to any works ), then someone else will!!' so, if you set any works up such as gas etc... and gas people say I am not effing doing that mate as I only do full installs - then you can rest assured that 'someone' will!

Tom

-------------------------
Tom .... ( The TERMINATOR ).

handyTRADESMAN ... haha

Castle Builders

Why did Nick Clegg cross the road? Because he said he wouldn't!

I can resist anything..... except temptation! ( Karl Gunn ).
 06 January 2013 10:39 AM
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briandoherty

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Originally posted by: DOUGIE1000
I repair gas boilers, in fact replaced PCB in my own com I boiler at home this morning, as I don't touch gas vales, gas pipe gas meter etc I can work on boilers without problem (we sub out gas works and also more importantly flue works).


In my post, I underlined the bit about registration not being necessary "provided this work does not involve disconnection of a gas fitting, i.e. breaking into the gas path or combustion system". On many (probably most) modern domestic boilers of the room-sealed type (i.e. the usual type today) the casing is part of the 'combustion system'; air from the air inlet system enters the casing and is then drawn from the casing by the fan and pushed into the combustion chamber. Gas Safe Register publication GSR work on gas appliances refers to 'decorative' and 'functional' casings.

If you remove a 'functional' casing, you are disturbing the combustion system and are therefore carrying out gas work. If you do this in your own home, you need only be 'competent', but if you do it for others as part of your employment than you must be both competent and registered.


Tom; I'm sure you know that the work you describe as doing for clients is gas work for which both competence (I'm not questioning yours) and registration are required... !

-------------------------
Regards,

Brian
 06 January 2013 11:51 AM
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mrcornbeef

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So if we take a cover of a typical combi and carry out electrical work which most sparks will have ,should we be concerned ??
 06 January 2013 12:07 PM
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alancapon

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I think only if you work on the gas-carrying parts or remove the cover for the combustion chamber.

Regards,

Alan.
 06 January 2013 12:52 PM
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briandoherty

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For ease of reference, the Gas Safe Register link I provided (to a document carrying HSE endorsement) states the following:

"Decorative casing: These cases can usually be removed by the consumer e.g. can be lifted off or are hinged panels and do not need to be unscrewed. A decorative case can be removed safely by the consumer or anybody else remembering to follow any warning labels and making sure you have isolated any electrical parts. However, if you are in any doubt, always use a Gas Safe registered engineer.
Integral casing: Many appliances have cases which form a seal around the gas carrying components e.g. burner, combustion chamber, etc as well as being decorative. If removing the case involves undoing a number of screws, this normally means it is a functional case and it should not be removed by the consumer or a person who is not Gas Safe registered.
"

For a room-sealed boiler, the 'combustion system' includes not only the flue but the air inlet pipe / duct (whether concentric or twin). For a functional casing as I described, removing it is gas work just like disassembling the air inlet pipe / duct. You don't need to go the extra step of removing the internal combustion chamber cover to have carried out gas work.

Whether or not sparks should 'be concerned' (as mentioned by mrcornbeef) depends upon whether or not they wish to interpret the Gas Safety (Installation and Use) Regulations differently to Gas Safe Register's and HSE's interpretation.

-------------------------
Regards,

Brian
 06 January 2013 05:30 PM
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mrcornbeef

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Thanks Brian
i suppose finding out if the cover is decorative is the point , checking the manufacturers info or calling them would confirm this.
 06 January 2013 09:51 PM
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briandoherty

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mrcornbeef,

I hope I didn't come across as heavy handed in my earlier reply. I've been involved with investigation of several carbon monoxide poisoning incidents over the last couple of years, and also with investigation of many more instances of boiler / flue installations resulting in unsafe situations which could have resulted in carbon monoxide poisoning. I'm therefore acutely aware of the forensic nature of such investigations, and of how those tradesmen who have been in any way involved in the installation come under intense scrutiny.

Pretty well all of the modern room-sealed boilers I've come across use the casing as part of the combustion air path, making it a 'functional casing' as described by Gas Safe Register / HSE. Furthermore, as detailed in Gas Safe Register Technical Bulletin 054, the following boilers (at least) are 'positive pressure', making the casing seal even more critical:

Potterton Netaheat 10/16 Glow-worm Fuelsaver 35F
Potterton Netaheat 16/22 Glow-worm Fuelsaver 45F
Potterton Netaheat 10/16 Mk ll Glow-worm Fuelsaver 55F
Potterton Netaheat 16/22 Mk ll Glow-worm Fuelsaver 65F
Potterton Netaheat Electronic 10/16 Glow-worm Fuelsaver 80F
Potterton Netaheat Electronic 16/22 Glow-worm Fuelsaver 100F
Myson (Thorn) Olympic 20/35F* Ideal Turbo 12
Myson (Thorn) Olympic 38/50F* Ideal Excel 30F
Myson (Thorn) Apollo Fanfare 15/30 Ideal Excel 40F
Myson (Thorn) Apollo Fanfare 30/50 Ideal Excel 50F
Trisave Turbo T45 Ideal Excel 60F
Trisave Turbo T60

Whereas a Gas Safe Register Registered Engineer could be expected to be familiar with these issues, i.e. positive pressure casing, combustion air path casing, etc., other trades may not. The risks are not insignificant, so it's probably best to leave delving around inside the casing to a Gas Safe Register Registered Engineer. If his / her electrical skills are not always up to the challenge, then by all means offer support, but be very wary of working on such appliances without being 'under the supervison' of a Gas Safe Register Registered Engineer.

-------------------------
Regards,

Brian
IET » Wiring and the regulations » Compressor

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