My problem is this - My iron trips the circuit breaker on the power side of
the House fuse board. This is a relatively new iron definitely less than 6
months old. We purchased the new iron because the old iron was doing the
same thing. Until this week I suspected that the problem was linked to the
wall socket, but 2 days ago the same thing happened while the iron was
plugged in to a socket in a different room.
My question is this - should I suspect that the new iron had developed a
short, or is the problem more likely to be related to the house power
The new iron is a different make from the old one so its unlikely to be a
design fault in the iron.
Many thanks for reading this far.
Which "circuit breaker" do you mean? Is it a circuit breaker just for
the single circuit with your sockets in it - one of say 6-10 similar-looking
a-bit-like-a-switch things in your consumer unit, marked (at a plausible
guess) "32A"? Or is it a wider breaker with a "test" button on it as well,
whose markings include "30mA" and maybe "80A" or "63A" which cuts power
to a number of circuits? Let us know: the former suggests an overloaded
or faulty single circuit, the latter a problem - or possibly a combination
of little 'problems' - with leakage to earth. Let us know, too, how soon
after plugging in the iron this happens - immediately? after a few
seconds or minutes? What happens if you plug the iron in on a different
circuit, e.g. the upstairs sockets (assuming they are on a separate
email@example.com wrote in message wrote:
My consumer unit has two sections lighting to the left, power to the
right. There are 3 or 4 lighting circuits and as you guessed 6 - 10
power circuits. To the right of the power circuits is a switch which
disables all the power circuits in one go.
It is that switch which trips and not the individual circuit breaker.
Consequently I loose power all over the house.
The lighting is not affected though.
The problem with this problem is that it is not repeatable at will.
Having reset the power we can resume ironing and the problem does not
recur maybe for days or weeks. But there is definately a problem
somewhere, and it always occurs when the iron is in use.
As a side issue the utility room contains a Washing Machine and Tumble
Drier, and in the past the conbination of these two in operation at
the same time has caused the power to be lost - but NOT house wide.
When they trip out it is only the circuit that goes ie one of the 6-10
little switches on the consumer unit.
I hope that helps
That's a 'split load' CU. The circuits don't actually *have* to be
split with only 'lighting' on non-RCD protected section on the left.
I'd really expect the immersion heater (if you have one) and cooker
circuit (if you have one) to be on this section too.
It's the RCD tripping when it sees too much leakage to earth, it
suggests that the element in your iron is a bit marginal as regards
insulation or that there is a loose wire in it somewhere that is
occasionally touching something.
It could also be that the sum of leakage from other appliances around
the house (computers and cookers are front runners on this front) is
enough so that when the additional leakage of the iron is added the
Well that's one good thing, you're not plunged into darkness when it
There are a number of possible causes/cures:-
1 The iron really is faulty, i.e. the element's insulation is poor
or there's a loose wire. It could be within specification and still
cause the problem. Replacing the iron would probably fix it. (But
see 2 below)
2 The sum of leakages from many appliances is adding up to trip the
RCD, the iron is just the final increment. Removing some of the
appliances which are likely to be leaky from the RCD side of the CU
might help. For example moving immersion heater and cooker to the
non-RCD side of the CU is quite allowable regulations wise and may
fix the problem. However it's quite a significant thing to change
for only a chance of fixing the problem. It depends on the CU how
easy it would be to do.
3 If 2 is the case then another approach is to add separate RCD
protected circuits for each (or some) of the circuits currently
protected by the one RCD. You can get RCBOs (combined RCD & MCB) to
go in some CUs, moving some circuits to the LHS of your CU and
protecting with RCBOs would probably fix your problem. This is a
relatively expensive cure though, but it does make your installation
much more user friendly.
4 The RCD may have got hyper sensitive and or may be at the
sensitive end of the allowable range. The only way to check is to
replace it really (though an electrician should have proper test
equipment to check it), fairly expensive again.
That's simply too much load tripping the MCB. It suggests that maybe
some rewiring and/or redistibution of load would be a good idea.
In uk.d-i-y, firstname.lastname@example.org wrote:
On the last point - it's not *that* expensive in my slightly dated
experience: 50quid 5 years back got me a wiring inspection by a very
competent local electrician, who spend time with his RCD-tester tracking
down the reason for nuisance tripping (combination of cooker elements
+ computers, as I'd suspected, along with an RCD right on the lower limit
of sensitivity: a "30mA" nominal out-of-balance trip rating means the
RCD must *not* trip at below half the rating, 15mA, and *must* trip
at-or-below the rating within something like 40ms; mine was tripping at
On the information you've now given, it does sound as if your installation
could benefit from a better allocation of circuits between the RCD and
non-RCD side, if not a dedicated RCBO or two. The immersion heater and
cooker circuits are prime candidates for moving to the non-RCD side, as
would be upstairs sockets (only likely to help with your nuisance trips if
you have interference-suppressed loads up there, such as computers). The
kitchen ring, if you have one that's separate from other downstairs sockets,
is also a fair candidate for non-RCD operation, but there's some conflict
between wanting to avoid nuisance trips from wash-mosh/dosh-wish, versus
the possibility that someone might run outdoor things from a kitchen
socket, and (back the other way) the loss of freezer/fridge contents if
the trip goes while you're away for two weeks ;-) One reasonable resolution
of the conflict is an RCBO dedicated to the kitchen circuit - this
combines the RCD and MCB functions in one unit, and allows the "full"
somewhere-between-15-and-30mA leakage "allowance" for just that circuit,
rather than across all the things on the RCD side of the CU. Costs of
RCBOs are falling - even a couple of years ago they ran at about 50quid
retail, now it's closer to 30-35; if a Regs tweak encourages their wider
use expect to see prices fall further.
Swapping circuits between the two sides can go from trivial to pain-in-the-bum,
depending on whether there's enough slack in the cables reaching the
relevant positions, and whether the CU has room for repositioned MCBs and
RCBOs (which from most manufacturers take up two positions in the CU).
If you feel it's beyond you, I'm sure an electrician can be found who'll
do suitable Magick, at the possible cost of encouraging you to upgrade
the whole of the installation to latest Regs standard. You might get a
decent deal if you combine the 'can you tell me what's going wrong' with
the 'can you sort it out then' aspects ;-)
HTH - Stefek
Our's have always done that, on different circuits with different
irons. Nothing else does it, at any time. As I can't find a fault on
the wiring I've put it down to water and electric in an iron not been
a good idea.
It is also worth pointing out that it isn't exactly a quality CU thats
been fitted, (it was here when we moved in), GE or Vynckier, never
liked those things.
Some of the higher quality RCD's have anti nuisance tripping
characteristics and can make a difference.
Obviously it would wise to check the wiring first to eliminate any
Check the rating of the MCB that trips in this event, it sounds as
though it is under-rated. Ideally You want a 32A circuit to the WM &
TD, if yours is on a 16A or 20A you may need to have a new circuit
installed, or use the appliances seperately!
When I first commissioned my sauna and spa, the RCD was forever tripping.
The manual said this was expected for the first few hours of use as the
heating elements (and there are lots of them) were new and could have
absorbed moisture. Somehow (perhaps someone could explain?) this trips the
RCD. After about a dozen resets all settled down as the manual said it
would. If its a new iron could this also be the case?
Your sauna heating elements have a heating wire, surrounded by mineral
insulation, with an earthed metal sheath around that. If the insulation
has absorbed a bit of moisture, it (to be anal about it: various ion
species now in solution and therefore unexpectedly mobile) will conduct
a small proportion of the electrickery - which would otherwise flow only
from live to neutral - from the heating wire to the earthed metal sheath.
Because the sheath is earthed, it's not dangerous to you, since the sheath
is kept at the same potential (a) as any other bits of metal in the sauna
- that's what your Supplementary Bonding is doing for you, and (b) as the
general mass of your surroundings. But the RCD is saying "hmm, there's a
bit more current going down the live wire than wot's coming back up the
neutral; don't like that; is it still going on? yup? ah well, time to
trip then". As the mineral insulation dries out from the heating, it
stops being nearly so conductive, and your RCD goes back to a state of
wariness rather than at action stations.
Although an iron *might* leak to earth a little more when first used than
after a while, I'd'a thunk it'd settle down much sooner than the 6 months
our original poster reports (unless in their household they have a
few-times-a-year ironing binge... like us ;-) It sounded more like the OP
had pre-existing leaks-to-earth which put their RCD right on the edge of
Ta for such a complete answer. I must admit to having some concerns when it
first happened and nearly sent the heater back, but the manual was most
definite it would happen and I was just being impatient. Never read
anything similar on any other electrical goods.
I must admit to not even owning an iron :-)
Well, when you can hang your shirts and linen suits up in the sauna, why
would you want one??? :-)
email me at
richard at olifant d-ot co do-t uk
We had the same problem with our tumble drier - it turned out the RCD (20
years old) was defective, and was tripping when a high current was taken (It
was rated at 100A/30mA, but was tripping at well below that)
If you can isolate the whole CO (If you have an isolator in between your CU
and your meter) then it is possible to change this yourself - however, if
you have any doubts to your ability in doing this, then it is time to call
If you go down the electrician route, make sure they have an RCD tester,
that way the can check it is actually faulty!
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