110V WORK TOOLS

someone somewhere
Member - 18 posts

As far as I know there's no requirement for 110v hand tools anywhere.
It was introduced but then revoked as being inpractical.
The qualification was, that should 240v tools be used they should be connected via an RCD.
An RCD offers better overall protection than centre tapped 110v supplies.

robert davey
Member - 4 posts

thanks for the reply, very interesting, can anyone else verify what "someone somewhere" has said

Pasc Ruggiero, CFIOSH, FRSH
Member - 41 posts

The safer of the two options is easy to resolve. Would you rather connect your body to 55V or 240V? (Don’t try!). You will get more than FOUR times the current (which is what kills) flowing through you with a 240V supply. RCDs/RCCBs are electro-mechanical devices. These fail and can be abused(not 100% reliable) and hence, require testing/maintenance. Also, if you are well insulated from earth/ground and you connect yourself between LIVE and NEUTRAL, the RCCB will ‘see’ you as a load e.g. a lamp, and is likely NOT to operate.

There isn’t a strict legal requirement to use 110V CTE (centre tapped earth) on a construction site but the conditions normally found in these environments usually only justify the use of voltages above this if special equipment is involved e.g. electric welding or some dry finishing trades. The applicable legislation, in addition to risk assessment, is Electricity @WR 89 and PUWER 98. HSE:HSG 141 (1995 and still valid!) - Electrical Safety on Construction Sites, gives further details. The use of 110V or less is well established on building sites other than some non UK companies or very small contractors. This, of course, does not provide justification.

Where conditions are similar or worse eg metal fabrication then the use of 110V or SAFER will apply.

PS: 55V and less can result in a fatality.

someone somewhere
Member - 18 posts

You are of course correct in all your comments regarding construction sites but I think the original question was one of whether all work tools have to be 110v.
The simple answer is no and not all hand held work tools are electric.
Other hazardous environments apart from construction sites have different requirements again.
Environments such as mines and oil and gas installations where not just concerns from indirect contact with a live source are the only hazard to the operator of the tool.
In such environments the risk assesment may call for air powered tools etc as in metal fabrication shops.

Graham Kenyon
Member - 33 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.

someone somewhere
Member - 18 posts

There's no doubting 110v is a step in the right direction and battery is a step further, but using 240v isn't inherently dangerous if used in the correct environment with appropriate measures in place.
Every work tool sold in every DIY establishment is 240v.
I personally believe you are more at danger from the types of hand held tools available rather than the supply voltage.
it would be interesting to see a comparison of types of injuries relating to hand held power tools.
I know I've never been electrocuted by a power tool but have received many other injuries from them.

Graham Kenyon
Member - 33 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 . .)

Pasc Ruggiero, CFIOSH, FRSH
Member - 41 posts

I believe the query refers to employment.

HSE: HSG107 states “nearly a quarter of all reportable electrical accidents involve portable equipment. The majority of these accidents result in electric shock….”

The DIY sector is probably worse!

Lower voltages are inherently safer.

I think everyone has acknowledged that the environment (risk) is important e.g 400kV overhead lines are acceptable.

Pasc Ruggiero, CFIOSH, FRSH
Member - 41 posts

Sorry, I seem to have got out of step. My posting @1218h was in response to someone...@1123h.

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

Graham Kenyon
Member - 33 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.

Geoff Porteous
Member - 22 posts

DIY carried out in the home by someone "Not at work" is not subject to any H&S legislation !!! Never has been.

Pasc Ruggiero, CFIOSH, FRSH
Member - 41 posts

Graham,

The “other legislation” allows the manufacturer to provide equipment (for DIY or employed work) at voltages greater than 110V.

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.

Graham Kenyon
Member - 33 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 - 33 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").

Carl Manning
Member - 8 posts

A forum with two lines of debate one reasoned and trying to be helpful to others and a second rather subjective view. There are clear advantages to lower voltage and this has generally been recognised by the 'construction industry'. In the home, DIYers are starting to use battery powered tools due to their convenience.

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.

Unfortunatley Electrickery is just that a magic science to those of us in the dark?

CDM 2007 applies to all construction except those specific exemptions listed in the 'Regs'

Graham Kenyon
Member - 33 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 - 33 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.