Continue to Site

Welcome to

Welcome to our site! is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

House electricity supply trips out

Not open for further replies.


Jun 22, 2008
Reaction score
Trophy points
Activity points
electricity tripping


Household mains electricity supply is tripping out….do you know why?

I live in a house shared by seven people…………….

For several weeks , I used to have two desktop computers on my bedroom table,

-the two monitors and system units were plugged in to a four-way extension socket, -

-this four-way extension socket was plugged into a single mains outlet in the wall of my room.
- - - - - - - - - - - - - -

Every night before I went to bed , I used to …….
1.) …..‘shutdown’ my two computers,
2.)……then turn off my room light,
3.)……..and then switch off the wall socket switch which fed the afore-mentioned four-way extension socket.

Little did I know that the act of switching off the wall socket into which the two computers were connected (part “3” above) was actually TRIPPING OUT THE ELECTRICITY SUPPLY TO THE WHOLE HOUSE (lights and wall outlets all down!)

I did not know about it, because I was going to bed, and had no light ON, and was obviously not using any electrical appliances, -so did not realise that I was tripping out the entire house – and just went off to bed.

Mayhem ensued.

Fridges defrosted overnight, people’s TV’s suddenly went off, phone chargers went off, etc etc…..though I did not know it was happening as I had gone to bed.

Eventually, other tennants were getting irate about the constant supply tripping, and two of the tennants in my house came to blows as one (wrongly) accused the other of tripping out the electricity deliberately.

Eventually I realised what was happening…… (as one night I tried to re-power my computers after switching them OFF, and they wouldn’t come back ON).

Please does any reader know why simply turning off the wall socket switch that fed a four-way extension socket into which were plugged two computers (that were both not running when I switched off the wall socket) tripped out the whole house?

Incidentally, switching this switch OFF did not always trip the supply, but most times it did.

electricity going out in house suddenly

Try this experiment to get more clues. After resetting the circuit breaker and not turning the computers on, turn off the wall outlet and see if the circuit breaker trips. Also try unplugging the cord from the wall outlet and do the experiment again.

From what you describe, it is the main breaker that is blowing. In most mains wiring inside a building there are subordinate breakers for different zones of the house. I once saw one house with about 20 breaker zones.

Do you have Earth Leakage Circuit breakers installed on the switchboard?
How old is the house?
How many breakers are installed? How are they wired?

One probable cause that comes to mind is when you switch on the wall outlet, evry thing is connected (computers and monitors). These have SMPS. These SMPS draw a huge surge current for a short while when switched on. This is making the circuit breaker trip. If you try powering the computers one by one, may be the issue will be resolved


actually this problem is nto happening when i switch ON the computers.

The problem happens when the computers are not in use (they are shutdown), The computers are off but plugged is when i simply unplug them that the house trips.

that is, when i either unplug the extension socket or switch off the switch on the extension socket

You are not drawing a large current when the breakers open. So I suspect you have ground-fault interrupter circuit breakers which sense a current imbalance on the hot, neutral and ground lines. You have some experimentation ahead, do a google search.

This can only happen, if you have a central earth leakage circuit breaker respectively RCD installed. In this case, disconnecting a load with earth to neutral short can trigger it, if the neutral is disconnected before the live line. The earth to neutral short can be either an easily detectable permanent short or a temporary short by a defective filter capacitor or overvoltage protector.

But I'm not aware, that central RCDs are used in an apartment house, except for a building site's temporary installation. Sounds rather like a DIY electricians than a professionals work.

I request you to just try the suggestion, there is no harm. I experinenced similar situation and based on the observation that is the solution that worked. Kindly drop a line if it does not work. If needed the details can be discussed.

thankyou i will look into these

I would check out the switch to see if it is broken, and accidently short circuiting the supply when switched "off". Exactly what type of switch are we talking about anyway? Switches are usually only used on lighting circuits. If you are using a switched circuit that is controlling a wall outlet, maybe the switch was under-rated (not rated for high enough current).

I would replace the branch circuit circuit breaker, since it should obviously be tripping before the main house breaker (supplying many branch circuits) trips.

I would throw away any sort of power strip that the computers are running off of, and replace it with a new one.

biff44 said:
Exactly what type of switch are we talking about anyway? Switches are usually only used on lighting circuits.

Depends whereabouts in the world the OP is, here in the UK it's rare to find a wall socket which isn't switched.

Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to