I’m also a retired electrician but I read Orchid daily. I’m an
Australian so things are a little different over here but many things
are the same. For a start we use 240 volts and 50 hertz mains. Over
here, I often came across your complaint. These “tingles” can
sometimes be due to very small voltages and the common “leccy” meters
may not even detect them. I will mention some remedies throughout
the article and suggest testing methods at the end.
If you do decide to “clean up” any earth connections or bonds as
mentioned below, PLEASE TURN OFF THE POWER FIRST at the main switch.
If there is a fault in your building, it may be passing current
through the connection you are undoing and you will complete the
circuit. Not good. We don’t like to reduce the Orchid newsgroup’s
It is best if a qualified electrician does the job but nothing says
you can’t be a pain and supervise them (you’re just extraordinarilly
fussy) or get them to allow you to do some jobs with them
"Tingles"may have many causes.
Basically, the earthing system in a building takes any (earth
leakage) fault current to ground for safety. If there is any current
leaking to earth and the earthing system has any resistance and you
form a better earth path than the building earthing system, then you
will get a shock or a “tingle.” As these “tingles” may be of very
low voltages - many electricians just discount them as they “aren’t a
shock hazard.” If the electrician’s meter isn’t sensitive enough to
read the voltage then they may consider it an "all in their head"
complaint and not seriously investigate any further.
Worse still, if there is a fault then a high resistance earthing
system may cause all of the earthed items in your house to be sitting
at any voltage up to your mains voltage. I have seen a "tingle"
complaint where all of the house was floating at almost mains
potential!! (Including the metal switchboard that I had to open to
turn off the power).
- Main Earthing System
The problem was often a bad earthing system often requiring an
additional (or two) earth stake (preferably extra long) driven and
connected to the existing earth stake. This was particularly the
case if there wasn’t an earth stake used but only a connection to the
metal water pipes (old system here) or soil conditions that weren’t
conducive to a good connection - sand, soil in drought etc.
Sometimes people would regularly water the ground around their earth
stake to ensure a good conductor. The connection to the earth rod
must also be a good connection though. Please see the comments
about this in Section 2.
Another problem is people cementing around the earth stake - it can
get dry and nothing can be done about it. We suggest a piece of 3
inch or 4 inch PVC pipe be used around the top of an earth stake to
keep the concrete away from it when cementing to allow access to the
A related problem was “tingles” from water taps - again it can be
the earth stake or the “earth bond” which is a wire joining metal
water pipes to the earthing system. Bad connections are a problem.
It also helps in the earth bond is done in larger cable then normally
used, especially if the bond runs any length, as this reduces the
resistance. Any reduction in resistance can be helpful when we are
dealing with small voltages.
Sometimes a section of piping is changed with PVC or polythene and
the pipe has sections insulated from each other. The water will
conduct the electricity so the separated metal sections need to be
"bonded" or joined together as well so that any current is goiing
through the pipework or wire and not the water. We occasionally also
had to bond the Hot and Cold pipes together under sinks etc.
Although rare, it sometimes worked - especially with newer "fancy"
- Good Earth Connections
Earth clamps or bonds to pipes or earth stakes must make good
electrical connections. If the clamp or pipe or earth stake has any
corrosion or oxide film where connections are made, it may need to be
replaced or the surfaces cleaned up with steel wool or emery and
redone. Over here, connections are then spray painted with spray
galvanising paint to seal them from the air and moisture.
- Bad connections to the Utility Power system.
A bad connection to the Utility Power system can be problem too. In
Australia the neutral conductor is bonded to the earth at each
installation. If the neutral connection to the building becomes high
resistance (for some reason they will sometimes burn off) then the
earth system has to carry all the current. Typical complaint here is
that the lights dim when we use the stove. I don’t know if the same
system is used in the USA (we call it the MEN - Multiple Earthed
Neutral system here - terminology may be different).
- Plugs, Sockets, Leads, Connections.
Although lower down the scale, the contacts in your power outlets
must be making contact and not corroded, overheated, or sprung apart.
Loose or oxidised wiring or connections in the fixed wiring can also
be at fault. Similarly, connections at plugs and sockets on leads
must also be in good condition and socket contacts in good condition.
Extension cords are common problems as far as having burnt or
corroded connections. Too small of conductor in any extension cord
adds to voltage drop and resistance problems. Again, a higher
resistance to earth allows you to be a better path than the cable.
Bigger is better, especially if you’re sensitive and large cabling is
vital for high current items (helps stop fires too). Transparent
plugs and sockets are available in Australia and allow visual
inspections without dismantling items.
If your plugs or sockets show any signs of heat damage they should
be replaced. Plug pins should not be corroded or heavily oxidised as
that can be a problem. Plug pins can be given a light "polishing"
but plugs should be replaced if heavily corroded or showing "burn"
marks. If you fit a new plug and notice thatit has arc marks again,
then you have a faulty socket. A faulty socket can destroy a new plug
very quickly and requires both the plug and socket to be replaced - a
pain if it was a new plug.
Any connections to an item’s metal work for earthing must be tight,
clean and not corroded or oxidised and the earthing screw not
painted. This last item seems common sense but I have seen many
items where the connecting lug or screw has been well painted and
impossible to ever be a conductor.
- Electrical Fault.
If you have an electrical fault to earth in your installation then
the earthing system takes that current to ground for safety. If the
earthing system has any resistance (see item 1 above) then it may
cause all of the earthed items in your house to be sitting at a
voltage somewhere between zero and your mains voltage.
If you form a better earth path than the building earthing system,
then you will get a shock or a “tingle.”
If the mains authority has a transformer or other equipment nearby
with a fault to earth (especially on the high voltage side), then you
may end up with a “voltage gradient”. This is because the ground has
resistance so the voltage doesn’t drop immediately at the earthing
point but reduces over a distance. You can be quite some distance
from a high voltage fault and get a voltage gradient effect. The
worst case scenario is if your body is in water e.g. swimming pool,
when a gradient of a few volts per yard can kill you.
- Ground Fault Interrupter (Safety Switch, RCD or ELCB)
Ground Fault Interrupters (called Safety Switch, RCD or ELCB amongst
other names in Australia and elsewhere) are great devices. They work
well but do have limitations. Operation just takes the common sense
fact that the current into an appliance through the Active or Hot
wire should equal the current out through the Neutral wire. Any
imbalance is leakage to earth i.e. a fault.
A Ground Fault Interrupter is normally partly mechanical in nature.
They must be tested (operation triggered) periodically to ensure that
the mechanics don’t freeze up and that they haven’t been damaged by
surges etc. Whilst they normally have a test button for testing,
there are cheap test devices available at electrical wholesalers that
allow you to test the actual tripping current - there are also very
expensive test units as well.
Why it won’t save you.
A Ground Fault Interrupter (Safety Switch, RCD or ELCB) WILL NOT
operate if you go between the active and neutral conductors whilst
insulated from earth. There is no imbalance, no earth current; it
sees you as another appliance working correctly and happily frying.
They also will not operate if the imbalance is too low. Thankfully
they are fairly sensitive unless damaged by surges etc…
Tests have also shown that they normally will not operate in the
"appliance drops into the bathtub with person in it" scenario. At
least here in Australia, PVC waste water piping means that the bath
tub is not an effective earth and you again have no imbalance…
If you have wet skin or puncture the skin the shock effect may be
far greater so they may not be as effective.
- Testing your electrical installation earthing.
This is best done by an electrician. In Australia the rules
stipulate a maximum of 4 ohms from the earth stake to any socket
earth. This is a maximum value and should be lower - the lower the
Testing is done by using a resistance meter or Ohm meter. The power
should be turned OFF at the main switch as any fault may energise the
It is best if the test is made to every power outlet (i.e. both
sockets of a double outlet) and that the method of testing an outlet
is by plugging a plug into it with only the earth wire being
connected to the plug as a meter connection - using a test probe in
the socket won’t detect a sprung earth and will scratch through quite
heavy corrosion. This ensures that the socket is making good contact
on the earth pin. Trying to wriggle the plug to see if it affects
the reading also helps show any faults. I have seen earth pins so
widely sprung that they could never make contact with a plug but the
test probe finds them easily.
The insulation resistance of each circuit should be tested
individually with and without appliances - plug all your appliances
in for a total insulation test under “operating conditions” and/or
test them individually. It is amazing how a few "slightly leaky"
appliances add up.
- A few other items to watch.
If you only occasionally use items with a heating element (tubular
metal style) and you are in a moist environment (like we are here in
the tropics) then they may absorb moisture. These tubular elements
have a fine powder inside to insulate the internal element from the
casing. This poweder is hydroscopic - it sucks up moisture - and the
end seals are not perfect. When you plug it into a Ground Fault
Interrupter (Safety Switch, RCD or ELCB), the leakage may be
sufficient to trip it. This may be worse here because of our higher
mains voltage. The standard remedy is to plug it into a socket not
protected for earth leakage and heat it up. It may take 5 - 10
minutes or even 30 minutes or so. It is then generally OK for a year
or so. My switchboards (4) each have a socket fitted just for that
BTW, “tingles” can also be caused by faulty elements in electrical
hot water systems - a fault that can get overlooked as they may still
be operating but faulty.
- Static Electricity
If you are in an environment with very dry air and especially if
there is “lino” or carpet or synthetic floor coverings, you may be
feeling static electricity discharges. In dry summer conditions, we
get complaints about polishers that are faulty - regularly that is
the problem. Try touching something that is grounded and then try
touching the first item again to see if it still “tingles.”
- Double Insulated items with Metal Cases.
The common item is a Stereo System or Radio Transmitter. The
tingles can be due to coupling by capacive or inductive effects. I
have seen a radio transmitter that really “bit” but was officially
"safe" and legal. The remedy is an earth wire fitted to a convenient
earth. This is allowed in most countries - if I remember correctly
it is termed a “functional” earth and not a “protective” earth. It
is normally illegal to fit an earthed cord to a double insulated item
but it appears that you can fit an extra earth wire - wierd huh?
I hope this helps. Regards, Brian Symons.
Sunny Mackay, Nth Queensland, Australia.