110V or 240V

ThomasH

Hi,

Just curious to know how does tradesmen decide if they need a 110V or 240V tools like drills, routers, etc.

I have a few mates that are in building and seems to buy 110V but also have mates that are carpenters and work mostly in houses and they buy 240V.

I am not a tradesman but need to buy a hammer drill for general work at my house and was wondering which voltage I should get.

Thanks
Tom

galwaytt

By law, only 110v tools allowed on any site. Period. It's safe to say your mates are only doing jobs in existing, houses, not new, on sites........

For DIY around the house - 240 is fine, but if you're going to step outside the door - 110v. The first wet day that comes, you'll thank me, believe me.....

squire1

Do you have a 110V supply in your house, or a generator? If not, then buy the tool that matches the supply you have. ie 220V.

110V is normally used on building sites before permanent supply is installed.

eoghan.geraghty

As galway says, by law only 110V hand held tools power tool allowed on site.
It is the law, even after permanent supply is switched on by ESB.
If you are buying 110V drill you need to factor price of 230V-110V transformer into purchase price.
If you only want this for odd jobs around the house, buy a 230V.
Or do as my friends do, wait til tradesman friend calls by and suddenly remember you need something done;)

ThomasH

Thanks for the replies.

I'll get a 230V as it is just for around my own house.

By "On site" do you mean new houses where there is no electricity yet?

but if you're going to step outside the door - 110v. The first wet day that comes, you'll thank me, believe me.....

Can you explain this to me please? I would not work outside my house if it is raining.

squire1

With a 110V supply, if you touch a live wire the highest voltage you can receive is 55V which is less likely to kill you than 220/240.

"On Site" probably means a building site because as mentioned it is illegal to use 220/240 on a building site. The problem arises when you ask when a "site" is no longer a site if you know what I mean.

Sonnenblumen

squire1 wrote:

With a 110V supply, if you touch a live wire the highest voltage you can receive is 55V which is less likely to kill you than 220/240.

"On Site" probably means a building site because as mentioned it is illegal to use 220/240 on a building site. The problem arises when you ask when a "site" is no longer a site if you know what I mean.

We only use 110V on all sites (outside), ie new , old and 'in between'. Apart from being a statutory stipulation, it is also safer. Mind you it isn't unusual to see the odd 'cowboy' with a 240V tool, but he's always the one looking for a connection.

we do not allow any 240V in our work areas.

Reyman

squire1 wrote:

With a 110V supply, if you touch a live wire the highest voltage you can receive is 55V which is less likely to kill you than 220/240.

.

Explain please ! How is it only 55 volts?

squire1

Rayman, I'm certainly no expert but the way I understand it is the centre point is connected to earth so the max amplitude is 55V.

There are better informed posters on here that might explain it better. The simple fact is you are less likely to be killed using a 110V tool than using a 230V tool, thus it is a safety issue.

Don't a lot of countries use 110V as domestic supplies? I wonder if anyone can explain why other countries dont bother. Probably something to do with the cost of the transforming equipment or the voltage drop off over long distances.

Reyman

Fine I'm just curious. Usually you'd work out the peak voltage of a two phase sinusoidal system by multiplying the RMS voltage (110) by the form factor or the square root of 2 =1.414. This gives a value of 155 volts peak to earth.

There may be some system of running the 110v across a centre earth giving 55v on either side of it .

I'd be curious to hear more if someone is familiar with this system

squire1

http://www.iosh.co.uk/index.cfm?go=discussion.view&forum=1&thread=23497&page=601

Rayman, you've got me interested now so I googled and came up with the above discussion on the merits/reasons for using 110V on site. They seem to indicate that although 110V is a recommended it is not in fact a regulation in the UK which is a surprise to me.

Hope it explains it somewhat.

rogue-entity

110V may be safer, but a shock from a 110V line can still kill a person. The voltage is not as important as the current, current is what kills, not voltage.

squire1

I'm not sure I agree. Yes, in the right circumstances, you can be killed by a shock from a 110V (CET) supply but it is unlikely. Current is formed by volts running through a resitance (human body). It is known that at higher voltage the resistance of the body reduces, thus increasing current flow. EG 55v running through 5000 Ohms produces 10mA (not plesant) but 230V running through 2000Ohms produces 115mA (possibly fatal). So the voltage level has a big part to play in determining wheather your work mates slag you off at lunchtime for being an idiot or call an ambulance.

Sorry, quiet day today. Google is great isn't it.:D

Reyman

An interesting website Squire. Your view of a 110 volt system having a centre-tapped secondary winding and a max 55 volts person to earth voltage is confirmed as correct.

An interesting sideline is that you must not only use 110volts but also an RCD in the primary transformer circuit as added protection

fred funk }{

rogue-entity wrote:

110V may be safer, but a shock from a 110V line can still kill a person. The voltage is not as important as the current, current is what kills, not voltage.

I agee, Volts shock, Amp's kill.

Using 110V you are less likely to be killed than if you were using 220V. All electricity is dangerous and can kill even at very low voltage.

fred funk }{

fred funk }{ wrote:

I agee, Volts shock, Amp's kill.

When I was in college the phrase "volts jolt!, mills kills" was drummed into us, 30mA passing through the heart was sufficient to stop it!

eoghan.geraghty

Just to your answer one of squire1's questions.

Don't a lot of countries use 110V as domestic supplies? I wonder if anyone can explain why other countries dont bother. Probably something to do with the cost of the transforming equipment or the voltage drop off over long distances.

If you halve the voltage, you double the current.

If you double the current,you increase the cable sizes,fuse/MCB sizes.So now you need a 10 square cable for your cooker with a 63A fuse.

You would also need larger transformers to reduce to 110V instead of 230V.

Uk engineers way back when decided on 230V so we got it too.

I can only think of USA as a developed country on 110V,remember seeing a programme on the subject years ago but cant remember why they went 110V.

eoghan.geraghty

Just to your answer one of squire1's questions.

Don't a lot of countries use 110V as domestic supplies? I wonder if anyone can explain why other countries dont bother. Probably something to do with the cost of the transforming equipment or the voltage drop off over long distances.

If you halve the voltage, you double the current.

If you double the current,you increase the cable sizes,fuse/MCB sizes.So now you need a 10 square cable for your cooker with a 63A fuse.

You would also need larger transformers to reduce to 110V instead of 230V.

Uk engineers way back when decided on 230V so we got it too.

I can only think of USA as a developed country on 110V,remember seeing a programme on the subject years ago but cant remember why they went 110V.

Oh squire1, I think from this further down in your link, 110V is more than just recommended.(yes I am really bored!)



Good Afternoon,
No H&S post nominals but I am an electrical engineer type. Can I refer you to BS7671:2001, other wise known as the 16th edition wiring regs. Section 604 deals specifically with the requirements for building sites. I have it open in front of me and to paraphrase, the only supplies allowed of 230v and above are for fixed flood lighting and for fixed or movable equipment above 3.75KW. There are also some office based items that can be 240V but, in essence, 110v is the supply stipulated by the IEE for use on a building/construction site.
Now, I know, the 16th edition regs are non statutory, however, as with many institute issued regs, they may be used in a court of law in evidence to claim compliance with a statutory requirement. In other words, the site manager must demonstrate that he is compliant with the regs as published by the IEE (an expert body) or that his system at least matches the safety standards as published.
Now going deep
Jim

Reyman

eoghan.geraghty wrote:

Just to your answer one of squire1's questions.

Don't a lot of countries use 110V as domestic supplies? I wonder if anyone can explain why other countries dont bother. Probably something to do with the cost of the transforming equipment or the voltage drop off over long distances.

If you halve the voltage, you double the current.

If you double the current,you increase the cable sizes,fuse/MCB sizes.So now you need a 10 square cable for your cooker with a 63A fuse.

You would also need larger transformers to reduce to 110V instead of 230V.

Uk engineers way back when decided on 230V so we got it too.

I can only think of USA as a developed country on 110V,remember seeing a programme on the subject years ago but cant remember why they went 110V.

The Americans went for 110volts for safety reasons.

As you say the current is doubled, but more important heat dissipation in the cables is a big problem. The heat given off for double the current is increased by a factor of four, so you need very large cables in your house.

They used to use 110 volts on the continent too for safety reasons. But now they've now gone to 220 volts also

CJhaughey

eoghan.geraghty wrote:

J

I can only think of USA as a developed country on 110V,remember seeing a programme on the subject years ago but cant remember why they went 110V.

Most of South America uses 110v interestingly 60hz is actually more efficient than 50hz.
Europe was 110v until the 1950's.

magicbastarder

rogue-entity wrote:

The voltage is not as important as the current, current is what kills, not voltage.

that's something like saying it's not your head hitting the dash at 60mph in a car crash which kills you, it's the brain trauma.

rogue-entity

No, its like saying, your head hitting the dash at 5mph, is like your head hitting a porportionally softer dash at a porportionally higher speed, no matter how much faster you hit, the impact would be the same, but the faster you are hit, the more it will hurt.

If you hit me with 1000A at 1V, nothing would happen to me, since the voltage isnt high enough to overcome my skins resistance, but if you reduced that to 10A at 100V, it would be enough to kill me, but at 100V the chance of me getting killed is less then it would be if it was 5A at 200V. It only takes 6mA across the heart to stop it, and kill you, your skin is an insulator, but a high enough voltage will overcome this and allow the current to flow through you.

eoghan.geraghty

CJhaughey wrote:

Most of South America uses 110v interestingly 60hz is actually more efficient than 50hz.
Europe was 110v until the 1950's.

Thanks CJ,I figured if USA were 110, most if not all of the Americas were too but didnt want to post what i'm not sure about.Never knew Europe used to be 110 either, very interesting.

Thomas H, did you get that drill or what?
Hope you're getting as much use out of it as we are out of your op.

davelerave

lads doing domestic work would be 230v site workers would be using 110v stuff