My Generator Study

Voicy said:
Please excuse the terrible drawing, but it equates to something like this:

View attachment 636316

Your "3 position selector switch" can be something like this:

View attachment 636318

The 3 position is so that you have:
1 - Mains
0 - OFF
2 - Gen

The OFF position allows safe switching in order to avoid spikes on any equipment - and to avoid any possibily of mains and gen ever coming into contact. This sometimes happens on 2-position switches.

Keep in mind that this selector must be rated to take your full mains capacity as it will be a permanent fixture.

The "Mains ON" / "Gen ON" indicators can either be a 230V buzzer or a lamp, or both in one like this:

View attachment 636320

I added protection circuit breakers for it - which comes in handy if you want to switch off a noisy buzzer. But the buzzer / lamp helps you see when you have mains or gen power at the inputs of your selector switch. If you don't go for a buzzer (or maybe even a buzzer that you can silence) you can leave the lamps on.

You can choose to have a permanent cable running to your Gen's output, or a dedicated socket that leads from the selector switch to your gen and nowhere else.

So if Eskom loadsheds you, you:

1) Start the Gen.
2) Check the status lamp to see that you have gen power.
3) Switch the selector from 1 "Mains" to 0 "OFF".
4) Wait a few seconds to allow fridge motors etc to stop completely.
5) Switch the selector from 0 "OFF" to 2 "Gen".

When you see the "Mains ON" lamp or buzzer activate, you can use the selector to switch back to Mains. Keep in mind that it's worth waiting a few minutes to see that the mains is stable...also allow a few seconds "OFF" to allow motors and such to stop completely before activating the mains.

EDIT: I forgot to change the title of SW4 to whatever your main circuit breaker in your DB is called. SW5 and SW6 are 2Amp circuit breakers - not used for anything other than monitoring the availability of each supply.
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Thanks very much for your effort. I really appreciate

The one thing that i may change is to use a 2-pole, 3 position selector. This will allow me to completely isolate the generator from mains when the switch is in the "Mains"position.

Also, the selector switch must be labelled in bold red "wait 5 second between clicks", to remind the dummies...
.
As @Geoff.D pointed out, there are a number of potential issues when working with power. It should not be easy to overload the Genny circuit. Luckily my db is logically laid out and it will be easy to split the feeds that need to be on standby power from those that will only be fed from the city main.
 
cbrunsdonza said:
Obviously me explanation to what I did was not correctly worded. No, I did not attempt to qualify for the 2019 Darwin Award.

The leads and plug points are all in isolation to the rest of the house electrical circuit.
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I think they might have assumed you were back feeding?
 
Trust|Nobody said:
Then what is the problem with backfeeding with the main switched off?
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The danger comes in not when everything thing has been done "properly" like a checklist, but when one step is forgotten or perhaps skipped. It has the potential to cause harm to your wiring , generator , someone in your house , your neighbours if you share a transformer and to someone working on an Eskom line.
An accident is not one thing going wrong it is usually a combination of things.

When it goes dark suddenly not everybody has a clear head and remembers everything, so rather err on the side of caution.
And make your life simpler.:)
 
heh heh! Reminds of what we did as kids.
Town: Somewhere in the Western Cape
Project: A private Intercom system Over the power lines ( all on same single phase) (long before anyone called these things PLC).
A simple setup where a signal was fed over the power feeds as a "party line" conference network.
Problem: How to introduce the signal onto the 220V via a normal wall socket. The electronics part was easy, all discrete components mind you)
Solution: a hand-wound transformer.

Outcome: One H of a big bang! Blew the main power distribution transformer for the entire suburb --- suburb power out for a week.

All kids involved had to appear before the local magistrate and threatened with 6 cuts each!
Punishment: 6 months community service.
 
Geoff.D said:
heh heh! Reminds of what we did as kids.
Town: Somewhere in the Western Cape
Project: A private Intercom system Over the power lines ( all on same single phase) (long before anyone called these things PLC).
A simple setup where a signal was fed over the power feeds as a "party line" conference network.
Problem: How to introduce the signal onto the 220V via a normal wall socket. The electronics part was easy, all discrete components mind you)
Solution: a hand-wound transformer.

Outcome: One H of a big bang! Blew the main power distribution transformer for the entire suburb --- suburb power out for a week.

All kids involved had to appear before the local magistrate and threatened with 6 cuts each!
Punishment: 6 months community service.
Click to expand...
I only know of this happening in Rondebosch area in the late 1980's...
 
I got mine this morning.

IMG_20190326_105032.jpg

A special thank you to Ryobi in Midrand for helping me locate one of the last few in the country.
 
Geoff.D said:
There is a saying: No earth is better than a bad earth. In other words, a generator floating and feeding equipment that is NOT connected to any other earth is less risky.

What does the manual say? Is there a E/L breaker on the generator?
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I am confused.
My manual says I must install a ground:

IMG_20190330_104456_670.jpg
 
IF the generator is used completely stand alone, with a CB protecting the live feed and connected to some appliances which are NOT earthed in any other way, then the earth peg is required to comply with regulations, especially, for lightning protection.
Hence the manual warning.
IF the generator is feeding into an existing DB where there is an existing earth. THEN the problems arise IF the generator is not properly bonded to that existing earth, with an appropriate earth cable connection. THEN the earth spike becomes a risk, and it is probably better to NOT to install the spike. But the generator should then be connected to the DB with the correct gauge cable, NOT a thin extension lead.
IF the spike is installed under these conditions that spike MUST be bonded to the existing installation earth point with a completely separate cable.
 
There are three aspects to all of this. The regulations, which are best ensured by an electrician, lightning and surge protection, and safety. The three do not always result in a common solution for all circumstances.
 
Geoff.D said:
IF the spike is installed under these conditions that spike MUST be bonded to the existing installation earth point with a completely separate cable.
Click to expand...

What would happen if I earthed my generator with a copper pipe in my garden, then backfed into my home using a 10A extension cable (suicide cable - two male ends) connected to one of my house plug outlets?

I don't understand how this could be a problem.
I thought the earth grounding was there only to protect against lighting strikes. If there are two separate grounds installed (one on my genie and the other on my DB), how is that a problem?
 
That suicide connection is a very bad idea besides being completely illegal. If your house develops a fault and anything goes wrong your insurance will be entirely void.

It is not about "normal events". It is about what happens under fault conditions. A fault in the suburb distribution could lead to fault currents flowing back into your property looking for that generator earth.

There are only two ways to use a generator safely and legally.

(1) As a stand-alone backup connected to a few appliances when LS occurs. Earthed and not earthed, it is an isolated system.

(2) And, as a properly connected backup supply to an emergency circuit done by an electrician and signed off with a CoC using the appropriate CBs contactors etc.

Any other arrangement is just not worth the added risks.

BTW, lots of older houses used the water pipes as earth. It could still be done that way, provided it is checked by an electrician. It is no longer the regulation approved way to provide an earth connection.
 
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Trust|Nobody said:
View attachment 635994

So I finished my generator study.
The Ryobi's are arranged in increasing total cost (equipment cost + running cost), as well as the Honda's.
It seems the Ryobi RG-2250i is the best option for me for a 2 kW load.

The Honda EU30is seems the most efficient at 5.42 R/kWh, but it costs R29k making the total cost R36800 (including operation costs).

Any comments?
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Are you a bean counter? Jokes aside.Thanks. Gave me a handy reference guide.
 
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