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SILICON
CHIP
www.siliconchip.com.au
Publisher & Editor-in-Chief
Leo Simpson, B.Bus., FAICD
Production Manager
Greg Swain, B.Sc. (Hons.)
Technical Editor
John Clarke, B.E.(Elec.)
Technical Staff
Ross Tester
Jim Rowe, B.A., B.Sc
Nicholas Vinen
Photography
Ross Tester
Reader Services
Ann Morris
Advertising Enquiries
Glyn Smith
Phone (02) 9939 3295
Mobile 0431 792 293
glyn<at>siliconchip.com.au
Regular Contributors
Brendan Akhurst
Rodney Champness, VK3UG
Kevin Poulter
Stan Swan
Dave Thompson
SILICON CHIP is published 12 times
a year by Silicon Chip Publications
Pty Ltd. ACN 003 205 490. ABN 49
003 205 490. All material is copyright ©. No part of this publication
may be reproduced without the written consent of the publisher.
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Farm, NSW.
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Editorial office:
Unit 1, 234 Harbord Rd,
Brookvale, NSW 2100.
Postal address: PO Box 139,
Collaroy Beach, NSW 2097.
Phone (02) 9939 3295.
Fax (02) 9939 2648.
E-mail: silicon<at>siliconchip.com.au
ISSN 1030-2662
Publisher’s Letter
Electricity is a boon; electricity
is a killer!
This month we have an article which highlights a
hidden hazard of domestic electrical systems whereby
the plumbing in a house can become lethal. How can
this be? It is mainly due to corrosion and it turns out
that your average plumber is more aware of the problem than most electricians. Why is that? Because if a
plumber replaces a length of copper pipe in your house
or needs to remove or replace your water meter, he can
be exposed to the risk of electrocution.
The reason for this is that heavy electrical currents can flow in your water
pipes and through your water meter. If the water meter is removed, there may be
the full 230VAC applied between the two pipe ends! If the plumber is unfortunate enough to touch the two pipe ends, he could be electrocuted. Fortunately,
most plumbers are aware of this and before they even think about removing
a water meter, they bridge across it with a heavy jumper lead – to provide a
continuous path for the hazardous current. They should do the same thing
if they need to replace a length of copper pipe elsewhere in your plumbing.
You can read about how this hazard comes about in the article, starting on
page 14 but even if you don’t read it, you should be aware of the basic message.
In short, if you lose the Neutral connection from your home’s switchboard to
the power pole in your street, your water pipes could hold this lethal threat.
Nor will you know anything about it unless you do some checks. All of your
electrical appliances will continue to operate normally, by the way.
Perhaps you may be thinking that because you have RCDs (Residual Current Devices or safety switches) installed in your switchboard that everything
is ‘hunky dory’. Well, the RCDs may well protect you and your loved ones if
one of your appliances develops an electrical fault but they will not give any
protection against the hazard of electrical currents flowing in your water pipes.
“Oh, well”, you might be thinking, “provided no-one disturbs the water pipes,
nothing further can happen”. Well that could be a tragic conclusion because the
loss of the Neutral connection can also ultimately lead to all the pipes in your
household becoming “live” and lethal. You could be electrocuted next time
you take a shower. Think that is far-fetched? There have been several cases of
this happening in the last few years. Ignorance is not bliss!
Indeed, the impetus for this article came about because of a letter from one
of our regular correspondents whereby some of his close relatives living in a
rental premises complained to the landlord about getting ‘tingles’ in the shower.
The landlord regarded it as trivial and passed it off, saying that the previous
tenants had lived with it for six years. But our reader knew better and advised
his relatives to complain to their electrical retailer. And just as well that they
did – they had lost the Neutral connection at the power pole and were living
with the substantial risk of electrocution.
Now I am not advocating that people should be tampering with their electrical
systems in any way. But people should know about our MEN (Multiple Earth
Neutral) system and how it can develop a hazardous condition. Furthermore, I
believe that people who know about this are fundamentally safer than the vast
majority of the population who are completely ignorant about the workings of
electricity. If you ever hear about anyone getting ‘tingles’ from their water taps,
make sure that they advise their electricity retailer immediately. They will get
an immediate response and the problem will be fixed.
Leo Simpson
Recommended and maximum price only.
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