Dangers of connecting load between live and earth


A

Abdullah Eyles

(flame guard on)

Please tell me (and others who don't know) the dangers of connecting a
load (lamp, motor, whatever) between the live (230V) and Earth
(instead of Neutral) in a standard supply.

In know it will cause the RCB to trip, but where there isn't such a
device, and considering that the load will be powered, what are the
dangers?

(I know that it by-passes the electricity meter, ie if the neutral
connection is removed, it can't measure the voltage therefore no
consumption!)

(flame guard off)

Thanks!
 
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W

Wanderer

On 3 Sep 2003 04:48:40 -0700, Abdullah Eyles wrote:

(I know that it by-passes the electricity meter, ie if the neutral
connection is removed, it can't measure the voltage therefore no
consumption!)
I'm afraid it doesn't! As long as there's a live feed through the meter
and a neutral that goes back to the company main fuse, your electricity
consumption is measured.
 
R

Ronald

Christian McArdle said:
The voltage on the earth may rise, giving life threatening electric shocks
to those touching metallic appliances. This will particularly (but not
exclusively) be the case if using a TT earth system with a disabled RCD.

Also, can I suggest just paying the electricity bill rather than attempting
to steal our electricity and putting up our electricity price you selfish
c*nt.
Why don't we tell him to go ahead and do it? That way we will get rid of him
when he electrocutes himself.
 
B

Bob Mannix

Christian McArdle said:
The voltage on the earth may rise, giving life threatening electric shocks
to those touching metallic appliances. This will particularly (but not
exclusively) be the case if using a TT earth system with a disabled RCD.

Also, can I suggest just paying the electricity bill rather than attempting
to steal our electricity and putting up our electricity price you selfish
c*nt.
In addition to Christian's delicate opinion on defrauding the supplier (!)
(whether that is your intent or not),

a) the physical problems he refers to in his first paragraph are hugely
amplified by the fact that someone else entering the property (for whatever
reason - emergency, illness etc.,) will not know this has been done and,
indeed, will assume that it has been wired correctly. To put people in this
position is selfish and antisocial.

b) this sort of activity drives the legislative process to restrict more and
more the ability of competent, responsible and unselfish DIYers to do their
own work. On this NG this is regarded as BLOODY antisocial. I count this as
a danger.
 
M

MrCheerful

Abdullah said:
(flame guard on)

Please tell me (and others who don't know) the dangers of connecting a
load (lamp, motor, whatever) between the live (230V) and Earth
(instead of Neutral) in a standard supply.

In know it will cause the RCB to trip, but where there isn't such a
device, and considering that the load will be powered, what are the
dangers?

(I know that it by-passes the electricity meter, ie if the neutral
connection is removed, it can't measure the voltage therefore no
consumption!)

(flame guard off)

Thanks!
You have read the dangers. Now a real story. My fathers house
(wooden construction) has been running everything through an earth for
many years. The first real problem occurred a couple of years ago for
the very reason another poster pointed out, the earth wiring was not
heavy enough for modern day loads, the wire became red hot over a
length of about two feet and set fire to the cavity it was in, luckily
the earth failed completely and the fire went out (how, only God
knows) I have since replaced the earth lead with some f'ing great fat
earth and everything works again. So in twenty or more years only one
fire which could have been foreseen and didn't (by luck) hurt anyone
 
M

MrCheerful

Christian said:
I hope you installed a neutral also? Genuine TN-C systems aren't
particularly suitable for domestic situations.

Christian.
Oh, yes the neutral lead is there too.
 
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B

BigWallop

geoff said:
I regularly electrocute myself - keeps the heart going
I was testing a couple of unknown jumbled mains circuits in a large junction
box yesterday and touched one that should have been isolated or so I
thought. Well Hey, that's why I was there testing everything. In through
my right arm and out through my butt. A real sore one. It don't half pull
muscles where I think muscles shouldn't be pulled. Felt as though I heart
burn and pins and needles for a couple minutes afterwards.

One installation I remember from a few years back, saw a single phase roller
shutter motor that was connected across phase and earth because the guys
that installed it used multi-core cable with no actual green/yellow marked
core and looked as though they'd mixed the numbering up. Well it didn't
half cause problems with the computers in building. Every time the door was
used, the computer screens would all go wobbly and looked as though a magnet
had been placed beside them. One of the sockets in the goods inward area
was giving everybody a shock when they plugged anything in. A floor heater
used to get hotter when the door was raised and colder when the door was
dropped. That was a weird effect that really got me excited.

It actually took a couple of hours to find the culprit because everything we
touched was live and it meant we had to isolate everything individually and
completely until we found where the fault was. When we found it, we
couldn't believe that it was something so simple as a mix up between a
number six and a number eight core in the multi-core cable. A couple of
hours and a lot of hassle and danger for something so simple.

So Abdullah, make sure you use the correct connection on any electrical
installation. The dangers are many and not just to life and limb. The cost
of repairing damaged equipment because of wrong connections is also rather
expensive.
 
A

Abdullah Eyles

Ronald said:
Why don't we tell him to go ahead and do it? That way we will get rid of him
when he electrocutes himself.
I know that electricity can be stolen by that method because I work in
a company making electronic electricity meters - one of our targets is
to reduce electricity theft by using techniques such as AMR and
pre-paid metering systems.

I know how to work with electricity, maybe not as much as yourselves,
but I have been working in high voltage switchyards for almost ten
years installing SCADA systems.

The question was asked in order to explain to a inexperienced friend
of mine who connected something wrongly - I realised that I couldn't
answer the question myself (ashamed grin...)

And to think that a burglar (c*nt or p**ck) would knock the door and
tell you he came to steal your valuables! LOL
 
G

Grunff

Abdullah said:
I know that electricity can be stolen by that method because I work in
a company making electronic electricity meters - one of our targets is
to reduce electricity theft by using techniques such as AMR and
pre-paid metering systems.
I must've missed way too many lectures in the ac theory modules.
I can see how you *could* make a meter that behaves that way,
but I just can't see why you *would*. Please (anyone) enlighten me.
 
D

Dave Plowman

I know that electricity can be stolen by that method because I work in
a company making electronic electricity meters - one of our targets is
to reduce electricity theft by using techniques such as AMR and
pre-paid metering systems.
It's a queer sort of meter that couldn't read when two conductors which
are effectively in parallel are reversed, or one isn't present.
 
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T

Terry

BigWallop said:
I was testing a couple of unknown jumbled mains circuits in a large junction
box yesterday and touched one that should have been isolated or so I
thought. Well Hey, that's why I was there testing everything. In through
my right arm and out through my butt. A real sore one. It don't half pull
muscles where I think muscles shouldn't be pulled. Felt as though I heart
burn and pins and needles for a couple minutes afterwards.

One installation I remember from a few years back, saw a single phase roller
shutter motor that was connected across phase and earth because the guys
that installed it used multi-core cable with no actual green/yellow marked
core and looked as though they'd mixed the numbering up. Well it didn't
half cause problems with the computers in building. Every time the door was
used, the computer screens would all go wobbly and looked as though a magnet
had been placed beside them. One of the sockets in the goods inward area
was giving everybody a shock when they plugged anything in. A floor heater
used to get hotter when the door was raised and colder when the door was
dropped. That was a weird effect that really got me excited.

It actually took a couple of hours to find the culprit because everything we
touched was live and it meant we had to isolate everything individually and
completely until we found where the fault was. When we found it, we
couldn't believe that it was something so simple as a mix up between a
number six and a number eight core in the multi-core cable. A couple of
hours and a lot of hassle and danger for something so simple.

So Abdullah, make sure you use the correct connection on any electrical
installation. The dangers are many and not just to life and limb. The cost
of repairing damaged equipment because of wrong connections is also rather
expensive.
Also if there was an insurance claim (EITHER FOR PERSONAL
INJURY/DEATH OR PROPERTY DAMAGE) the insurance company might be
unsympathetic. It might decline to pay the claim in full or
reduce the amount; on basis that problem was caused by an
electrical problem that the owner was aware of and should have
had repaired? That has actually happened!
PS. Wiring errors: Apart from safety, due to a wire colour mix-up
(or ignorance?) we had a three phase motor running 'backwards'
(I figured for months)! When the phases were reconnected,
correctly, the motor, now running 'forward' driving an air
circulating fan blew accumulated dust in ducts over every thing
in my department. We sent the staff home and lost four hours of
production! Strangely we didn't get any dry cleaning bills,
although were prepared to pay them!
 
A

Andy Wade

Couldn't meter electronics work in the same way as timer
lightswitches that don't need a neutral? Across a whole installation
there must be comparatively few occasions when current flow is zero
and a small rechargeable battery could keep the meter running.
Therefore any current flow through live to earth would be metered.
Powering the meter's internals is one thing: measuring the energy consumed
is another. For the latter you need to sample both voltage and current. P =
V * I * cos(phi)[1], then integrate over time using electronic or mechanical
counters. A minimum of 3 terminals is required; in practice 4 are used
(with a neutral commoning block) for convenience of wiring.

Electronic meters do have backup batteries to maintain clock times (for
multi-rate tariffs) and provide non-volatile storage of the registers.

I have [2] an electronic Economy 7 meter made by Ampy Automation and have
noticed that the LCD display goes blank if there's a power cut. It looks as
if the battery holds up an absolute minimum of electronics.

[1] If you want to be pedantic, V & I here are the RMS values of the
fundamental frequency components of voltage & current. (Harmonic
currents contribute to apparent power - VA's but not watts - so
shouldn't be metered).

[2] 'spose that should read "EDF have, in my house"
 
O

Owain

| PS. Wiring errors: Apart from safety, due to a wire colour mix-up
| (or ignorance?) we had a three phase motor running 'backwards'
| (I figured for months)!

We have that to look forward to when we harmonise our wiring colours with
Europe.

Owain
 
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O

Owain

| "Owain" wrote
| > Couldn't meter electronics work in the same way as timer
| > lightswitches that don't need a neutral?
| Powering the meter's internals is one thing: measuring the energy
| consumed is another. For the latter you need to sample both
| voltage and current.

Ah, yes. <tears up patent application for fraud-proof meter>

Owain
 

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