External hookup point for power generator during power outages?

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Devilz

9 posts

Wannabe Geek

#315556 25-Jul-2024 15:50

Anyone know whats involved in NZ to get an external plug on your house to hookup an emergency generator during power outages? Seems all the videos about it are US based and show a power switchover type unit with a metal plate to stop you switching the mains back on when using the external generator, just wondering if anyone has ever got a NZ type version of this done for their house? Just wondering what sort of parts an electrician would be charging for on the outside box (1960's house, already moved the main fuses inside but the old external fuse box with the main on/off switch is outside the house)

Got a generator ive used a couple of times during power outages using the extension cords to get to required things, but would be nice to have a single hookup point to keep the lights running etc (and just switvhing off the extra unneeded high power usage devices from the fuse box during the outage to not overload the generator)

Scott3

3970 posts

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#3264303 25-Jul-2024 16:20

Bunnings has a kit for order:

https://www.bunnings.co.nz/briggs-stratton-manual-transfer-switch-accessory-kit_p0054807

My understanding is the equipment is fairly simple. A 3 position switch with off in the middle to ensure the grid and generator are always isolated from each other, a 2 pole example is below. Plus an appropriate inlet socket, and a cord to connect that to your generator.

https://fazcorp.co.nz/products/manual-change-over-switch-63a-2-pole

The changeover switch has 3 positions:
Position 1: uses the primary power supply
Middle position: disconnects from all supplies
Position 2: uses the secondary supply

Devilz

9 posts

Wannabe Geek

#3264307 25-Jul-2024 16:46

perfect, just what I was looking for, a list of bits to tell an electrician to install

typical NZ high price for some plastic bits with a bit of copper in them though, but expected 😁

SomeoneSomewhere

1804 posts

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#3264311 25-Jul-2024 16:54

This is documentation from K&N: https://www.krausnaimer.com/fileadmin/user_upload/Kraus_u_Naimer/Pdfcat/Local/NZ/Generator_Connection_Switches.pdf

I am still disappointed that no reputable MCB manufacturers produce a DIN rail interlock kit.

Juicytree

141 posts

Master Geek

#3264359 25-Jul-2024 17:02

I have had a plug fitted to the last three houses that I've owned. As mentioned, it requires a changeover switch to replace the house main circuit breaker. I've had a waterproof plug on the end of a cable hard wired into the internal wall of attached garage with sufficient length to run it outside (and out of hearing). My generator is petrol and on wheels and is 5 kilowatts. I keep it under the bench in my garage wired to a trickle charger and then just wheel it out when needed. I had an electrician wire it with a matching socket on the end of about 50cm of cable and hard wired into the generator. I am still able to use the standard three pin sockets on the generator if required for other uses.

It has amazed me how much it can run in the house without stressing. LED lights make an improvement in generator's capacity to cater for the household load nowadays. It's great to be able to watch the disasters unfold on TV. My only weakness is holding sufficient fresh petrol for a long outage.

traderstu

332 posts

Ultimate Geek

#3264456 25-Jul-2024 21:57

I had one done recently in conjunction with our solar instal, 2 phase power. Included was a changeover switch, 32amp inlet plug on the wall, 2m lead with 32amp plug on one end and a 10amp plug on the other. All up, including labour, $950 inc GST. I already had a 2kW generator, hence the 10amp plug, but the wiring is heavy enough that I can use a larger generator in the future if required.

The sparky wired it up so that none of the heavy loads connect to the generator (heat pumps, HWC, oven, hob etc) but all of the other circuits (wall sockets, lights), regardless of which phase they are connected to on the mains, are run from the generator. This means all of the essentials like fridge, freezer, internet, pump, lights run from the genny - I just have to be careful that I don't try to run too much at the same time.

While power cuts here are few and far between, the convenience of this seems like a no brainer.

RunningMan

8955 posts

Uber Geek

#3264530 26-Jul-2024 09:37

Changeover switch: https://www.trademe.co.nz/a/marketplace/building-renovation/electrical-lighting/switches-switchboards/switches/listing/4832393883

richms

28187 posts

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#3264593 26-Jul-2024 10:11

Anyone know of a solution when you have several sub panels to get selected loads only running on generator on the sub panels?

Richard rich.ms

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FineWine

2981 posts

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Nurse (R)

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#3264640 26-Jul-2024 11:58

My brother is a retired electrician and I forwarded this topic to him. Here is what he had to say. NOTE: He did his apprenticeship in Wellington in the sixties, then went to sea for 20 odd years, returning home to work down in Taupo for the big power generating companies down there. He hated domestic work, crawling around under houses and in roof spaces.

I have connected up several generators as emergency power supply over the years but there must be NO possibility of the generator feeding back into the grid and so the change over systems must be fool proof so this does not happen when the grid power comes back on.

There has been incidences of where people have plugged in a generator to a power point to back feed to the house switchboard which have dire consequences when the mains power comes back on. The only way this could work, you have to have a mighty big generator so that the generator can force feed, synchronize (sine wave), be in phase (for three phase ). For single phase no cross over of phase and neutral, correct voltage and frequency and proper earthing so you don't get circulating currents.

Also make sure the generator supplies a pure sine wave and has a good governor speed control otherwise you will have dirty power which is no good for electronics.

A ship I was on many years ago we supplied power to Auckland C.B.D when the city lost most of its power due to an under ground cable fault. We supplied 20 mega watts and it worked well but we had to run the Gas Turbine to generate the power, bloody expensive. I often wonder who paid for this as to run the turbine for 24 hours was near to $100,000 in fuel.

Whilst the difficult we can do immediately, the impossible takes a bit longer. However, miracles you will have to wait for.

Devilz

9 posts

Wannabe Geek

#3264665 26-Jul-2024 12:45

I was working in the CBD during those power outage time :) Good times....

Luckily moved the critical servers to a remote office 48hrs before the power went out, and the company also got a generator housed in a shipping container installed outside the building in the CBD as well with a mightly big power cord just for our floor :)

The generator I got at home a while ago is just a 4500W Peak inverter pure sinewave one which also has a remote control for power on/off which is handy, kept the fridge/servers/tv/netflix running quite happily with a few extension cords for a day or so once, but having a single hookup point would have made it easier having the light switches work in the rooms...

I need to get the power cable running from the side of the house to the main box upgraded to support 60+amps at some point as its still the 1960's original running under the roof to the outside fuse box which got mentioned to me when i had to have the external from the pole to the side of the house wire replaced when it melted and started sparking in the rain one night (old rubber original cable as well) they put in a smaller fuse on the pole as he said the inside house cable it plugged into couldnt handle the higher amps.

So when i get that replaced might go ahead and get the external hookup done at the same time seeing as they'll be pulling the main power etc.

SomeoneSomewhere

1804 posts

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#3264689 26-Jul-2024 14:01

richms:

Anyone know of a solution when you have several sub panels to get selected loads only running on generator on the sub panels?

There aren't really any miracle solutions here. Options include:

Manually switch off large loads when starting the generator. Easy enough for a manual transfer switch situation where you're getting the generator out of the garage, fuelling it up, plugging it in etc. Some colour coded labels and printed instructions should help.
Multi-core cables to the sub-boards with an essential and non-essential feed.
Pilot wire from the main switchboard to contactors in the sub-boards. If you use normally open contactors, the contactors are burning a few watts continuously and can get hot and loud. If you use normally closed, they'll only disconnect the load once power is available so not much use for reducing inrush.
Contactors with some kind of PLC/automation. Again, you need the contactors to be normally open so that the electronics have time to wake up and decide whether or not to connect the load.
Some kind of latching relay or motor-operated breakers with shunt trips. Problem is you need to store enough energy to trip them in a power loss, or use an undervoltage release that's not much different to having a contactor powered 24/7.
Automation at the loads rather than the switchboard. Works great for stuff like aircon, refrigeration, process that's on automation anyway. Not so great for random domestic load.

raytaylor

4014 posts

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#3265121 27-Jul-2024 13:18

We did this recently as a result of the week long power cut in napier after cyclone gabrielle.

Electrician installed a manual switchover with a 10 amp breaker on the generator input and a check meter which shows current wattage. With a bit of re configuring, he got it so the hot water cylinder remained disconnected when the generator is running.

There is an outdoor male socket next to the fuse board which we use a short extension lead between the generator and the socket.

The reason why I went with a standard male type I socket, and not a high current caravan plug is because a generator rarely gets used, and i am not likely to do the 3-monthly maintenance on mine so it may fail when its needed. I can use any other generator that I can find when its needed since they all have standard type I outputs rather than limiting myself to only high-wattage generators.

Also for consideration is that electric cars often have type I sockets for camping or running tools. A car with a battery range of 200kms will run our refrigerator and assorted laptops, modems and chargers for a week or two in an extended cut.

Vehicle to grid applications wont work as they still require the grid to operate as a sync source.

During the week of no power at home, I hooked up some deep cycle batteries to some solar panels laying in the driveway and a 12v inverter which was able to run most things including the refrigerator and some lights, most of the time without the loud noise.

We only started up the generator to run some high draw appliances like the microwave, and use some camping gas stoves for cooking so the rest of the time, like if we had an electric car, it would be silent.

Ray Taylor

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