Comments by Graham Kenyon

Graham Kenyon
Member - 26 posts

I'd say that the minimum for Building Regs conformance doesn't mean you meet all other legislation under all circumstances.

Was this an inadeqaute assessment by the designers under CDM ?

Graham Kenyon
Member - 26 posts

QUOTE: "To me, work in close proximity to HV switchgear means that you are able to touch the switchgear. "

That's what I'm trying to establish from Craig - and yes, the company I work for does sometimes have to send IT and Control engineers into switchgear rooms or transformer/substation pens. (As you point out, we have training, permits and additional PPE from the operator's SAPs.)

But if "close proximity" means working close to the fence around a small sub on a housing estate, for example, then the risks of tall equipment falling, work at height (and again falling, even if no overheads) and excavation are very real.

All this work requires special consideration.

Graham Kenyon
Member - 26 posts

QUOTE "A forum with two lines of debate one reasoned and trying to be helpful to others and a second rather subjective view"

If the "Second rather subjective view" applies to my comments, please note that this is my professional opinion.

I'm a Chartered Electrical Engineer.

Graham Kenyon
Member - 26 posts

QUOTE"As for 55-0-55 that still kills if someone operating the eqpt doesn't understand its construction and then places a modification that alters the earthing arrangement. "

Assume you are talking "domestic" here - altering the earthing arrangements on the respective circuit and generating that hazard would be an offence under Building Regulations, Part P.

But how would you achieve this if the supply were a sealed transformer to the relevant standards, with 2-pole protection, and earthing made solidly inside the sealed tranformer. (For example, the sort used for providing such outlets in factories etc.) ?

(Such a tranformer would be required to conform to BS7671 if we were providing the outlets as part of the fixed wiring).

Graham Kenyon
Member - 26 posts

It seems absolutely ludicrous that we should have to put up notices that say "Hot Water may be Hot". What a revalation !

Using arguments about children doesn't work either - because some children are too young to read the notices.

BUT

It should be an absolute requirement that places who have decided to remove plugs to prevent flooding of bathrooms, provide mixer taps - otherwise, no-one can safely use the "Hot Water" !!!!

Graham Kenyon
Member - 26 posts

There are potentially lots of hazards working near, around and with HV switchgear and transformers.

But this depends on:

1. How close.

2. What type of HV switchgear and transformers and where the conductors are fed from.

3. The work activity itself. (e.g. if only near the HV equipment, what's the risk of touching overhead lines, things falling onto the HV equipment, getting too close so that open conductors can arc to your employees or work equipment, etc.)


For example, working withing a HV substation switchgear room, you'd normally provide flame retardant clothing (in case, for example, the switchgear blows an arc if it operates when you are near it), specific training, and consideration of other electromagnetic effects on your tools, test equipment, etc. Also, would consider provision of non-conducting ladders, tape measures, etc.


Do you have a specific problem or activity you'd like to discuss ?

Graham Kenyon
Member - 26 posts

Quote "There is no requirement in the CDM Regulations regarding ”operation and use”. Maintenance duties are very limited and does not apply to DIY. If you disagree, please cite the Regulation(s) that apply. I have given a more detailed response to CDM v operation/use on 21 February 2008."

11 (3) (e) covers the designer's obligations to consider H&S risks in "operation and use" if the premises is designed as a workplace. This does not, generally, apply to "Dwellings".

11(3) (d) specifically covers maintenance of the permanent fixtures and fittings of a structure - and there is no exemption for a "dwelling".

This is where I was coming from.

Since 110 V tools are generally available in the UK, is it "reasonably practicable" to provide some 110 V outlets, from a 55-0-55 V "reduced low-voltage" supply, as part of:

(a) the fixed installation in every dwelling (At present, I'd say "NO", because of the chances 230 V tools will be used for DIY, and the availability of 110 V transformers for tradespersons); and

(b) the fixed installation in a workplace where portable tools will be used frequently (And here I'd say "Yes" - "Must Do").

Graham Kenyon
Member - 26 posts

I understand what you are saying, but:

1. The designer of an domestic electrical installation MUST conform to CDM Regulations, except if this is done as a "DIY" job. The ONLY reason that a 55-0-55 supply is not provided in domestic installations for the use of tools, is that it is not thought "reasonably practicable" - because the DIY power tools themselves are not 110 V, they are 230 V.

2. The regulations that apply to the electrical safety of power tools for DIY - the Electrical Equipment (Safety) Regulations, and, where they apply, the Supply of Machinery (Safety) Regulations - do not impose a requirement for 110 V, as you quite rightly say.

They are not likely to for reasons of Harmonization. The same legislation applies to power tools for Commercial/Industrial use.


The point I was making, if you re-read the posts, is that it is not reasonably practicable to provide 110 V tools for DIY use in the UK at this stage. Nor is there a legal requirement to do so.

However, there's no doubt that it's much much safer.

TO BE QUITE BLUNT, WE'D BE BETTER OFF WITH 110 V LAWNMOWERS AT HOME POWERED FROM 55-0-55 v SUPPLY, THAN A 230 V SUPPLY WITH RCD - but I don't think that we'd be allowed to legislate for that, over and above the harmonised requirements, because it would restrict free trade !!!

(This doesn't mean I believe all appliances should be 110 V, only hand-held portable appliances, power tools and lawnmowers/strimmers/other garden tools).

Now, I understand that we've been under pressure to also "conform" with industrial tools used on construction sites etc., i.e. do away with the 55-0-55 V system altogether.

I OPPOSE THIS STRONGLY. I HOPE THAT OUR REPRESENTATIVES ON THE RELEVANT COMMITTEES (including IEC TC64 for Electrical Installations) CONTINUE TO HOLD OUT FOR THE 55-0-55 System.

Graham Kenyon
Member - 26 posts

Quote: "I would now add: Of course, that the HSWA74, legal requirement for risk assessments etc does not apply to DIY work."

Yes, but a manufacturer still has responsibilities for the safety of their products under other legislation.

And with the fixed wiring installation in a dwelling, CDM Regulations apply regardless - needs to ensure safety SFARP in operation, use and maintenance

So there is still a need for risk assessment, and appropriate measures including the Hierarchy of Control where necessary.

Graham Kenyon
Member - 26 posts

I understand what you're saying about 240 V, but the 55-0-55 V system is preferred under the Hierarchy of Controls - it almost "removes" the electric shock hazard, and certainly reduces the effect, as the voltage to earth is limited to 55 V. Fire is still a possibility - but overcurrent protection (and RCDs) help here.

Is it "reasonably practicable" - yes it is.


Why doesn't it apply for DIY? Well, in terms of practicability, the supply at home is 230 V, and it's not reasonably practicable to reduce that. A transformer, for the frequency of use, is not practicable either. And overall, the frequency of use of the power tool is less. . .

(But on the other hand, DIYer is less experienced . .)

Graham Kenyon
Member - 26 posts

I understand the UK has been under pressure to drop the "reduced low voltage" system by CENELEC as part of Harmonisation - other CENELEC countries use 230 V as their standard voltage on their construction sites.

I hope that the representatives on the relevant CENELEC committees continue to hold out, as 110 V is a life-saver.


Many customer sites I work on don't allow hand-tools unless they are either battery or 110 V, regardless of whether it is a construction site, "industrial" plant-room, or workshop environment. If no 110 V supply nearby, a transformer must be provided, and extension leads used for tools must be on the 110 V side, not the 230 V side.


BTW, a hazard from battery drills - if the direction control is not placed in the "safety" position, I'm aware of some injuries resulting from the drill starting accidentally whilst being carried between places of work.


Please try and encourage (and I know this is difficult):

(a) drills not to be transported with bits in.

(b) battery drills to have the direction control left in "safety" position when the tool is not in use.

Graham Kenyon
Member - 26 posts

I re-read this thread and the following statement just caught my eye:

"Sounds to me like the person washing their hands was at fault for allowing the gel to drip."

Gel, by its very nature, drips. Surely, a person can't be at fault if the gel drips - only for failing to wipe it up after it has done so (if they notice it).

Since it is reasonably foreseeable that:

(i) The gel will drip; and
(ii) Someone might not notice the gel has dripped,

then surely it's the organisation providing and operating the hand-cleansing facility to ensure this foreseeable hazard is addressed, based on risk assessment ?

Wouldn't the best option be to monitor these cleansing stations to look at the frequency of spill, to support a risk assessment ?

If the frequency is so low it's not worth doing anything else, maybe reminder notices at each station similar to: "If you spill gel tell someone" or "If you spill gel wipe it up"

Graham Kenyon
Member - 26 posts

What if the person whose hands it dripped from was a member of the public ?

Graham Kenyon
Member - 26 posts

Phil,

Please understand it's my intention to help here and nothing else.

If you feel you need to understand more, you could get hold of the following standards (although they are a bit pricey):

- BS EN60335-1 (this is the basic standard for safety of domestic and similar appliances, but also is used for commercial cleaning equipment etc. Specific requirements for certain products are contained in additional standards B S EN60335-x - but bS EN60335-1 contains the basic safety requirements common to most appliances).

- BS EN60950-1 (standard for safety of IT equipment).

- BS1363-1 (standard for safety of UK plug, but also contains the table that determines cable size selection and fuse rating for the combinations acceptable under Plugs and Sockets Regs).

In addition, the following legislation is of interest:

- Electrical Equipment (Safety) Regulations (This implments the Low Voltage Directive in the UK, and is available to view/print freely from www.opsi.gov.uk).

- The Plugs and Sockets (Safety) Regulations (again, free to view/print from www.opsi.gov.uk).


There are also courses from organisations like ERA Technology, where you can learn about appliance construction for safety.


Whilst it could be argued that the above material is aimed at Designers, if you don't have prior experience of electrical and electronic equipment, and the EU legislative safety requirements and assiciated standards, you'd definitely benefit, especially if you are going to be a professional inspector, rather than work in-house on a limited set of equipment that you are familiar with.

Graham Kenyon
Member - 26 posts

But if the appliances don't conform to BS EN60950, they must afford an equivalent level of safety. Surely, because BS EN50116 is the EU standard for production-line testing, then that must be used as the benchmark test to see if the appliance does afford that equivalent level of safety ?

This is a personal choice, but unless there are very exceptional circumstances, I do not accept equipment that can't withstand that test, because I don't believe that it affords equivalent safety to the EU standards, in which case how do I know the appliance is safe ?


There are some unusual exceptions, but in general if it's got a UK plug and is earthed, 500 V d.c. test ccp to earth should not damage the equipment.

Again, though, warning that you should only do tests if you are sure of what you are doing.

I'd ask, though, if you can't do the 500 V d.c. test for a Class I appliance, have you really achieved much in doing your inspection and test ?

And certainly if you miss out the earth continuity test, this is not adequate at all.


Back on insulation resistance, the appliance will be subject to "transients" well above 500 V on a regular basis (pluggable IT equipment needs to meet Overvoltage Category CAT II to be safe in the EU).

Again, this may put the user at danger.

So, whilst I understand the guidance, my knowledge and experience leads me:

1. to investigate conformance during inspection.

2. make a judgement and either FAIL or Test - and FAIL if the appliance fails the test.

But this needs the relevant knowledge and experience.

Graham Kenyon
Member - 26 posts

QUOTE "For most items of IT equipment the 500 volt insulation test should not be carried out as it can damage the appliance."

Is this really the case ?

Certainly, the 8A or 25A a.c. test for earth continuity may damage IT equipment (These tests can blow PCB tracks if the current happens to flow down a parallel path, depending on where you attach the earth probe or clip - perform the test at 100 mA a.c. or 200 mA d.c. if you are unsure, but move the lead as recommended in the IEE CoP).

But a 500 V d.c. insulation resistance test between ccp and earth (ccp is "coupled current-carrying pair", i.e. L&N connected together) should not normally damage IT equipment. According to the BS EN50116 standard, which is for routine production-line testing of IT equipment to BS EN60950, all IT equipment should be tested like this on the production line, but at a much higher voltage (typically 1500 V a.c. for 1 second for Class I components). Sub-assemblies may be tested separately.
The 500 V d.c. test should not stress the components in the IT equipment - but an a.c. test would, which is why the time is reduced to 1 s from 60 s between production-line test and the original type test.



Of course, the guidance must always be to only conduct tests that you are sure won't damage equipment - so don't do it if you are not sure yourself !

Graham Kenyon
Member - 26 posts

QUOTE "Electrical faults are the second biggest cause of fires,the main one being arson"

This statement seems sort of "obvious". Even if we drive down the number of fires to a minimum, it may well continue to be the case, because electricity is a source of energy that's "always on" until the protective device (fuse, circuit breaker or RCD) operates.

RCDs don't protect against short-circuits between current-carrying conductors, only where a current-carrying conductor shorts to "earth" (either in the appliance, or through materials or people).

And if fuses and circuit breakers only let through enough energy so that a fire could not start, you'd not have enough power available.

Add that to the fact that now with the cessation of smoking in enclosed areas, In most workplaces, there aren't many other sources of ignition that are spread throughout the building (e.g. flames localised in a gas appliance) - and you can't see or smell electricity until something is going wrong !


This leaves us with a "what's reasonably practicable" situation I suppose. In other words, define what level of inspection and testing is "reasonably practicable" for your particular premises, using the guidelines in the IEE Code of Practice for In-Service Inspection of Electrical Equipment (for appliances and fixed equipment), and IEE Guidance Note 3 "Inspection and Testing", for the electrical installation itself (which can also be a fire hazard if faults are not noticed).

Graham Kenyon
Member - 26 posts

Hey - it's not my real opinion. Just questioning where all this might go.

But I agree with Jack - jokes should NOT be a cover for real or vindictive bullying of any kind.

Graham Kenyon
Member - 26 posts

Yes, poor judgement and it should not have been said.

The problems as I see it, is that English (well English spoken in UK and the Irish Republic at least) is full of idiom and metaphor - sometimes defined long before our time.

Our humour can play on puns.

The issue is that we probably don't see the harm in others viewing our statements literally. For example, the Barclaycard chief did not really refer to the Muslim sect as "bad" - but it remains the case that taken literally it's actually many times worse than just "bad". But UK English is not always (at present) a literal language.

We in the UK have worried about words like "postman" and "policeman" (it was OK for me to learn the words at school, but 20 years later had to start using "postal worker" and "police officer").

It seems as though we have decided that the roots and common/colourful use of a language are being questioned on the grounds of discrimination. Isn't it about time our fellow EU countries dropped the "gender" element of their languages, which must by now be seen as discriminatory by the standards of a modern EU citizen with English as their first language ?


Back to English - languages change and develop with the times. Maybe we are moving to a point where clear, concise and well spoken English is required in the workplace, and even regional accents and variations (which sometimes cause offence) should be stamped out ?