What to do for the safety of my home portable generator & of appliances?

What to do for the safety of my home portable generator & of appliances ?

When national power company's power goes off i turn my generator on and with the help of selector knob i change the selection on to generator power (means where generator power is connected to the selector) and the generator power is utilized by the appliances .... but problem is when the national power comes live and while generator is running and its power coming through if one of selector(s) or its any of the contact or point get shorted to each other then the generator power and the national power would also short each other so they may cause a short circuit so what protections should i use and where to connect that protection (whether fuse or breaker or whatever) ?

Never try to connect your generator to the company power circuit together! Always use a good strong power switch to separate external and internal source. When the mains is off, switch your home circuit to your internal generator. Use a small lamp on the mains line to see when it comes back, THEN switch the internal generator off and ge to the mains. Aways isolate both sources and measure generator voltage if you use it.

You should use both, firstly safe switches that don't cause a short (sounds self-evident at first sight) and secondly circuit breakers dimensioned at rated generator current.

means first switch off the generator supply and then select the national mains supply with a power switch selector ......... ???

As pointed here already, set up switches so that you never feed power to power company lines. Safety of your generator is secondary issue here. The primary reason is, there may be repair man solving power outtage, expecting cold lines as he has disconnected them from feed. And suddenly you make them HOT!

I lived in a house which had a transfer switch installed. The house wiring could receive either utility power or generator power.

The switch was in the circuit breaker box. A cable came from the box, ending with a plug for plugging into a generator.

It was impossible for generator power to go out to the utility power wires.

Most residences do not have a transfer switch.

BradtheRad said:

I lived in a house which had a transfer switch installed. The house wiring could receive either utility power or generator power.

The switch was in the circuit breaker box. A cable came from the box, ending with a plug for plugging into a generator.

It was impossible for generator power to go out to the utility power wires.

Most residences do not have a transfer switch.

Click to expand...

If there is no transfer switch, I would recommend to install the main power line available after the meter and the main fuse in a special wall outlet. All in-house utility and power network will be installed in a cable plug. The generator will also have an equivalent of a "wall plug" (most have it).
Then no special switch is needed. The user simply plugs all loads into one of two wall outlets whichever available. A good idea is to put a lamp or a voltmeter to each outlet to see where the power is available.

Such arrangement does not allow to connect the two power supplies together.

Would anybody provide me the schematics for this ?

I use a three position 63A rated switch. Position 1 goes to the generator cables, the center position is OFF, all connections are broken and Position 2 goes to the incoming AC mains. It is impossible with this switch to join any generator connection to any incoming power wires. You probably should keep a permanent Earth connection or at least provide your own if conditions permit.

Link to the switch I use: https://www.tlc-direct.co.uk/Produc...=adwords&kw=&gclid=CMOYspHqgboCFXDJtAodXAUAJA

There is some debate about whether the output of your generator should have it's neutral and Earth connections joined together. Some generators already have an internal link. The reasoning is that if the AC from the generator is completely isolated (floating), it is unlikely that any Earth leakage trip (ELCB) in your circuit will ever operate. Depending on your electricity company, you may not have one of these anyway.

Brian.

RANT:
I do not understand why the leaders of some countries allow their electricity grid to be much too weak for its citizens.
Electricity does not grow on trees then if you live in a desert with no trees you don't have enough electricity.
Electricity is made from waterfall turbines, windmill turbines, steam engines that burn coal or natural gas and steam engines heated by nuclear.

Here in North America the electrical grid was designed, is upgraded and is maintained to produce enough electricity for everybody now and in the future and it is very reliable.
I can't remember when something failed and stopped my electricity. A few years ago for a few minutes?
END OF RANT.

Here in the UK, the grid "National Grid" is also very secure and reliable but many people like myself are in very rural mountainous locations and some 30 miles from the nearest grid connection. The power reaches here via a long chain of transformers and overhead cables and that is where the problems creep in. It also an area of very high rainfall and regular 100 mph winds so the overheads are frequently under strain. I would guess we get a significant (> 30 minutes) black out on average around 3 - 4 times a year. The longest was for 3 days and most of that was tracing where water had penetrated a long underground section and rotted the insulation. The cable was around 40 years old and of an outdated construction, 4 copper cores (3-Phase and neutral), each wrapped in waxed paper with a spiral steel sleeve wrapped around them which also acted as an Earth connection. The outer weatherproof layer was cotton bandage soaked in tar, it must have pre-dated PVC!

Brian.

Here in North America the electrical grid was
designed, is upgraded and is maintained to
produce enough electricity for everybody now and
in the future and it is very reliable.
I can't remember when something failed and
stopped my electricity. A few years ago for a few minutes?

Click to expand...

https://en.m.wikipedia.org/wiki/Northeast_blackout_of_2003

Keith

Here is some picture gallery from that moment:
**broken link removed**

List of world major power outages
https://en.wikipedia.org/wiki/List_of_major_power_outages


I think that bigger electric power systems including power network for transmission and power production is like domino.


Best regards,
Peter

I remember the big blackout 10 years ago. We never had a blackout like that before so we celebrated.
Luckily it occurred mostly during daylight because it happened in summer when daylight is for a long time each day.