110 volts

[Phil Pascoe]

Is there any reason other than site safety why 110v is better than 240v? I suppose it makes your power tools a little less stealable (more difficult to sell on) and a bit more traceable maybe, but can anyone think of any other reason?

 

[MMUK]

Longevity and power.

A 110v drill, for the same torque and overall power of a 240v drill, will have a smaller motor.

For instance, a 240v SDS+ drill is normally 700w-800w on 240v. An identical output drill on 110v will be 550w-600w or thereabouts.

110v is just as lethal as 240v in the wrong hands.

 

[Dee J]

Safety, purely safety. The output of the 110 volt transformer is centre-tapped to earth - so the maximum live-earth potential is 55volts (mostly harmless). 230volt mains has the neutral near earth potential - so the live is 230volts from earth (sometimes fatal). What more reason do you need when using powertools whilst knee deep in mud!

Dee

 

[Dee J]

Longevity and power.

A 110v drill, for the same torque and overall power of a 240v drill, will have a smaller motor.

For instance, a 240v SDS+ drill is normally 700w-800w on 240v. An identical output drill on 110v will be 550w-600w or thereabouts.

110v is just as lethal as 240v in the wrong hands.

I'd like to see the maths on that. Less watts rating = less power out (unless there are any grounds for improved efficiency?). And of course to get the same power (watt) rating at 110 volts, current will have to be more than double that at 230 volts. So thicker mains lead, heavier switch contacts etc.

110 volts is less lethal, as in my previous reply - when centre-tapped to earth - reducing live-earth shock to 55 volts.

Dee

 

[John Brown]

"I'd like to see the maths on that."
+1

 

[twothumbs]

I know people always say that it is 110 for safety but I am also aware that 110 can be dangerous so a bit confused. USA uses 110 for domestic circuits and it is slower less safe and in my opinion not so good. But it isnt my subject. What I do know is the transformers are bloody heavy. Did site generators not run at 110 at one time? Best wishes ...and dont put your fingers in the holes.

 

[Myfordman]

USA homes use both 110 and 220v circuits depending on the appliance. Generally speaking portable appliances are 110v.
Home workshop equipment will be a mixture of the two voltages.

MM

 

[n0legs]

Longevity and power.

I'd like to see the maths on that. Less watts rating = less power out (unless there are any grounds for improved efficiency?). And of course to get the same power (watt) rating at 110 volts, current will have to be more than double that at 230 volts. So thicker mains lead, heavier switch contacts etc.

110 volts is less lethal, as in my previous reply - when centre-tapped to earth - reducing live-earth shock to 55 volts.

Dee

Correct.
Hence the yellow plugs being 16a rated.

Lower volts always means higher amps, well it did when I was learning elastictrickery.

Whilst Pat testing I failed many transformers due to faults on their primary side.
Also when I was with the electricity board a gas explosion occurred due to workers using power tools, 110 wasn't so safe that day.

It ain't the volts that get you it's the amps, been more than a few mechanics killed and that's 12 volts.

 

[n0legs]

Did site generators not run at 110 at one time? Best wishes ...and dont put your fingers in the holes.

Yes, still available.

 

[wizard]

i have had lots of electric shocks the worst was 12v

 

[DMF]

None of the 110 tools i have from site days had smaller motors than 240 versions if available, aside from the shock considerations (which i don't understand but will take as a truth from the HSE) for me the main safety thing has always been better connectors meaning harder for water to get into a 110 socket than a 240 one, its easier to use with gloves on and generally a stronger cable for dumpers and stuff to run over.

I do think there is something in them lasting longer than 240v tools though, i've still got every 110 tool i've ever bought and can't say the same for 240, maybe its the transformer acting as a balance providing nice clean power or whatever but i go 110 if i can.

Dean

 

[CHJ]

..I do think there is something in them lasting longer than 240v tools though, i've still got every 110 tool i've ever bought and can't say the same for 240, maybe its the transformer acting as a balance providing nice clean power or whatever but i go 110 if i can.

Dean

More likely down to insulation breakdown in armature/commutator, lower voltage pressure* with similar insulation standards.
*(effectively only 55 volt to frame/earth if used with safety transformer.)

 

[DMF]

More likely down to insulation breakdown in armature/commutator, lower voltage pressure* with similar insulation standards.
*(effectively only 55 volt to frame/earth if used with safety transformer.)

Yes this sounds much more likely all round!! As i said i don't know about electrics to that level.

I'm a tight wad though so don't just bin things, both were Christmas prezzies from an ex, decent tools just 240 and both were taken down to the shop to see if they could be repaired and both diagnosed with knackered motors. Only used for diy now and then as well and not had the level of work there site equivalents did either, i know this is far from a conclusive scientific test but never the less it has made me lean towards 110, even though i'm not on site now if i can get tools 110 rather than 240 i will.

Dean.

 

[No skills]

Some interesting views on 110v here. Yes the plugs/sockets are much better suited to exterior/poor condition use - similar fittings can be had for 240v though.

As somebody that has to work in inches of water with multiples of 415/110/240v cables running by my feet I have to say that keeping the cables in good condition and making sure theres rcd protection on everything possible is possibly the most important thing you can do to keep safe, I don't recall ever having a shock from a 110v tool - few tingles from faulty or just soaked 240v stuff - had a hole blown through a glove I was wearing from a faulty 415v plug Recently I dropped a steel panel on a 240v line whilst standing in water, didn't actually noticed I had cut the line until I looked round and saw the power out (was still holding the panel).

Thinking about it the only big shocks I've had have been whilst indoors in the dry working on circuits - isolate the circuit dummy...

Before you all start getting on those high horses - I'm not saying this is the way people should work, you are all in charge of your own H&S, if you don't think something is safe then don't do it, simple.

If you do find yourself working in those conditions then welcome to hell :evil: I'll be there with a mental grin and a strange pitchfork come angle grinder contraption. Ps bring some ear defenders, its noisy...

 

[CHJ]

I tell you what is interesting, getting a taste of anything with 400HZ, talk about penetrating the little nooks and crannies. Managed to avoid contact with 1200 and 1600HZ stuff thank goodness.

Don't ever stand on top of a metal skinned aircraft in the rain and pick up a valve voltmeter to move it where you can see it, some fool may have designed it with a capacitor/inductor filter earthed to the case.

 

[RossJarvis]

Is there any reason other than site safety why 110v is better than 240v? I suppose it makes your power tools a little less stealable (more difficult to sell on) and a bit more traceable maybe, but can anyone think of any other reason?

Another good reason for choosing 110v is that you can buy tools from America, which aren't available over here, or are cheaper and use them fairly easily. Plus, if you want to take your tools over there they'll work.

 

[No skills]

Yeah but its a long walk.

 

[Shrubby]

Aren't 110v tools a throwback to the 70s and metal bodied tools without double insulation ?
Other European countries don't have 110v sites. Germany has 230v isolation transformers for wet masonry tools fitted with electronic protection RCD/GFI and 42v for people grinding metal in confined spaces
Matt

 

[cutting42]

You have had the correct answer by Dee, it is 100% down to safety. Most accidents caused by an electric shock around the home are not death by electricity but falling off the ladder, down the stairs or other accidents caused by our reaction to a 240vac shock. On a site the consequences are potentially even worse as you are on scaffolding, down a hole etc.

To repeat Dee, the 110v side of a site transformer (known as the secondary) is a centre tap transformer with the tap at ground potential. The other ends of the wiring are at 55v. Therefore if you are standing in a puddle (ground or earth potential) the maximum voltage you can get a shock from is 55 volts rather than the 240 from regular mains.

As has been pointed out the voltage does not kill, it is the current that does that and not much is needed. Around 30mA in the wrong place will stop your heart. Voltage is needed to overcome the resistance of the skin and somewhere around 10 - 20 volts will do the job on you hands and about 5 volts on your tongue. Realistically you do need to be extremely unlucky to die from an electric shock, the risk is more from what you do to yourself reacting to the shock.

If you want to try for yourself, try taking a spark plug lead off the spark plug and sticking your finger on the end whilst the engine runs. You will not damage your self as the amps are very low, but you will get a hell of a shock and it will hurt.

 

[AES]

@CHJ:

Agree 100% - 400 Hz is NOT funny (actually, it hurts like hell)!

A point for those not in the know - aircraft (normally) have both 3 phase (AC) + DC - civil a/c are 110V @ 400Hz & either 12 or 24V (nominal). But back in the (not so good) old days when I worked on military a/c the AC was usually 200V @ 400Hz and that DOES hurt. DAMHIKT

No idea about power supplies on building sites but over here (Switzerland) you often see building sites with quite big temporary "transformer boxes" tapped into a nearby fixed local distribution "transformer box". 3 Phase (220V @ 60Hz) is just about standard all over here but I've no idea if the big stuff used on sites (like cranes) uses the 3 Phase and the hand-held stuff uses single Phase (and no idea of the voltage/s either).

Interesting stuff on this thread. As basically a mechanical bloke I find all these electrons wizzing silently and invisibly along wires a bit off-putting sometimes (especially on Airbusses with their - for me - often weird "illogical" software logic). Fun!

Krgds
AES