230 volt hand held power tools

[GoldDigger]

Curious, if two fingers (one on each leg) touched two line conductors, wouldn't the current to ground be much lower then when only touching one?

I know its an odd question.

Yes.
And yes.
(That "one finger on each leg" had me going for awhile.)
The degree to which the ground current was reduced would depend on the symmetry of your body and the skin contact points. It might be enough to avoid tripping a GFCI.

 

[mbrooke]

Yes.
And yes.
(That "one finger on each leg" had me going for awhile.)
The degree to which the ground current was reduced would depend on the symmetry of your body and the skin contact points. It might be enough to avoid tripping a GFCI.

My exact thoughts. Think of two balanced 120 volt loads line to line, it is possible to break the neutral and theoretically measure zero volts across both points.

I apologize for saying legs, I was trying to avoid using the term phase since that would indicate a 3 phase system which would not be symmetrical relative to earth.

 

[Besoeker]

On a UK building sites or industrial sites 110V (55-0-55V) is the maximum voltage allowed for power tools.

Why anyone would even want 230V is a mystery to me.

Because it is nominal single phase that most appliances work with?

 

[iceworm]

It is an NEC violation to install 208 or 240 volt receptacles in dwelling units for appliances less than 1400 VA.

I have to get inspections and I don't lie to inspectors.

Bob - be careful. I don't want you to trip amd fall off your pedestal. Be that as it may, we all knew you would not tend to lie to an inspector and I absolutely agree. Besides the fact it is wrong - there's no percentage in it.

Seriously: I've got two 240V, 20A receptacles in the garage. and one 240V, 20A in the master bedroom. They were shown on the prints - nobody bothered to ask. Had anyone asked, the answers were, "The one in the master bedroom is for a future through-the-wall AC - if we decide we want one, the wall is framed for it. The two in the shop are for a table saw and wire feed. And who knows - I might want to get a decent air compressor."

Another good answer is to put a note on the prints, "For appliances greater than 1400VA."

What I don't get is why is this even a consideration?

Now if it is an OSHA issue - as opposed to a dwelling - different story.

the worm

 

[kwired]

That's still just 120V potential to ground. That's normally what you worry about.

I hear people talking about getting shocked by 240V and I wonder if they really were touching both phases ( I doubt it).

We do switch 277 volts (to ground) quite often as well.

Bob - be careful. I don't want you to trip amd fall off your pedestal. Be that as it may, we all knew you would not tend to lie to an inspector and I absolutely agree. Besides the fact it is wrong - there's no percentage in it.

Seriously: I've got two 240V, 20A receptacles in the garage. and one 240V, 20A in the master bedroom. They were shown on the prints - nobody bothered to ask. Had anyone asked, the answers were, "The one in the master bedroom is for a future through-the-wall AC - if we decide we want one, the wall is framed for it. The two in the shop are for a table saw and wire feed. And who knows - I might want to get a decent air compressor."

Another good answer is to put a note on the prints, "For appliances greater than 1400VA."

What I don't get is why is this even a consideration?

Now if it is an OSHA issue - as opposed to a dwelling - different story.

the worm

Do they use many air conditioners where you are? Maybe portable ones would be more common then permanent ones I guess.

 

[iceworm]

...Do they use many air conditioners where you are? Maybe portable ones would be more common then permanent ones I guess.

I put one in the appartment we were in when bride was pregmant. Picked one that would fit between 16" studs and ran on 120V, 15A. Lot of years ago. She really liked it.

When I built the current house, I framed in for a 24" wide AC, put a 240V, 20A receptacle next to the spot, insulated and rocked the hole, sided over the outside. We don't expect any more kids, but maybe we would want an AC a few days a year. Never needed/wanted it, never put one in.

Portables are pretty inefficient. They don't have an outside air intake for the condenser, so cooled inside air is exhausted to cool condenser - not efficient. But they are cheap and don't require any building structural mods. I see some.

ice

 

[Tony S]

Because it is nominal single phase that most appliances work with?

You know damn well it isn’t.

Its bit safer than 245 to earth. I started under the M&Q act in 1974, the maximum then was 50V 25-0-25. Getting power tools was getting to be a real problem. AEG I think it was, would make drills for us at about 4X the cost of 110V but we had to buy a dozen at a time.

M&Q relaxed the rules to 110V 55-0-55 in about 1982/3. We were happy, we could get jig saws and things that had never been available before.

 

[mbrooke]

You know damn well it isn’t.

Its bit safer than 245 to earth. I started under the M&Q act in 1974, the maximum then was 50V 25-0-25. Getting power tools was getting to be a real problem. AEG I think it was, would make drills for us at about 4X the cost of 110V but we had to buy a dozen at a time.

M&Q relaxed the rules to 110V 55-0-55 in about 1982/3. We were happy, we could get jig saws and things that had never been available before.

Couldnt they just go with assured earthing (earth proving system) and special 10ma RCD?

 

[Besoeker]

You know damn well it isn’t.

Its bit safer than 245 to earth. I started under the M&Q act in 1974, the maximum then was 50V 25-0-25. Getting power tools was getting to be a real problem. AEG I think it was, would make drills for us at about 4X the cost of 110V but we had to buy a dozen at a time.

M&Q relaxed the rules to 110V 55-0-55 in about 1982/3. We were happy, we could get jig saws and things that had never been available before.

I know damn well otherwise.
Appliances that work on 230V.....and I did say appliances.
I have a Black and Decker that does. And a soldering iron.
Our washing machine, electric iron, an oscilloscope, electric kettle, microwave oven, electric heater,

Most of the tools in our workshop do. Jig saw. circular saw, soldering irons, extraction fans for the soldering booth, grinder, linisher, pillar drill, etc... In fact our workshop and test bay have just 400/230. There is no 110V.
We are a manufacturing concern. Our output is mostly variable speed drives some up to 6,000 kW. Of course everything portable has to be PAT tested. And that's fine.

I could go on but, in deference to this being a US site, I won't.

 

[Tony S]

Do you go on site with 240V hand tools?

Your workshop is your concern and your legal responsibility.

 

[Besoeker]

Do you go on site with 240V hand tools?

Your workshop is your concern and your legal responsibility.

I was simply answering your point in post #36:

Why anyone would even want 230V is a mystery to me.

 

[kwired]

It is starting to get to the point where some people don't even use plugged in hand power tools anymore - the batteries for cordless tools these days have pretty impressive capabilities and/or the tools are much better optimized to deliver high toque and last quite a long time compared to what we had not so long ago.

I heard at least one power tool manufacturer even has a coffee maker that runs on their tool batteries.

 

[Besoeker]

It is starting to get to the point where some people don't even use plugged in hand power tools anymore - the batteries for cordless tools these days have pretty impressive capabilities and/or the tools are much better optimized to deliver high toque and last quite a long time compared to what we had not so long ago.

Yes, indeed.
One of my service guys uses a battery powered Fluke oscilloscope. Mine, a Tektronix, is mains powered with a 230V mains lead.

 

[mbrooke]

Ok, dumb question.:dunce: How many more times is 230 volts dangerous then 120?

 

[Tony S]

4

 

[iceworm]

4
I’m English so what do I know?

Hummmm I remember reading something about,"mad dogs, englishman, and the noon day sun"

(That is suposed to be humoress (is that a word?) teasing - not mean)

But hey - I'm an Alaskan. What do I know?

The Worm

 

[GoldDigger]

A humoress would be a female humor (humour in UK).
In Alaska it would be the humorus, a relative of the walrus.
In the rest of the 50 the word you were looking for would be humorous. Or even absolutely hilarious.

 

[Jraef]

Ok, dumb question.:dunce: How many more times is 230 volts dangerous then 120?

it's a known fact that if you are killed by 240V, you are twice as dead as if you were killed by 120V...

 

[kwired]

Ok, dumb question.:dunce: How many more times is 230 volts dangerous then 120?

there are many ways one could look at the hazard level, plus you have to consider some other conditions such as in the US - it is likely center tapped and is only 115 to ground, but in European systems it is full 230 to ground on most applications. More voltage will push more current through the same resistance - often a person's body when this safety issue comes up.

So say we have a fixed resistance of 10 ohms and apply 120 volts to it - we get 12 amps current and 1440 watts of power is used.
Take same 10 ohm resistance and double voltage to 240 and we get 24 amps current but 5760 watts of power is used.

Current alone isn't what kills you - it is the power that cooks the flesh, doubling voltage applied across a fixed resistance quadruples the power consumed in the circuit.

Problem with human safety and shock hazards is 120 volts is still plenty high enough to easily kill you, but does need right conditions so there is no definite answer as to what is safer. More people are injured or killed by 120 volts because they are around equipment that operates at 120 volts to ground on a fairly regular basis. Kind of like chances of being hit by a car are much less if you seldom are on or near roadways where they typically operate.

 

[DrSparks]

One of my journeymen wired a temp panel incorrectly and I had a 240-volt sawzall for about a minute until it started smoking. Boy did it cut fast!