Generator Transfer Switch

Forums › Home Workshop DIY › Generator Transfer Switch

sootyandsweep

16 posts

Geek

#248897 15-Apr-2019 13:50

Hi All.

Wondering if anyone has had any experience with getting one installed? I got a 5.5kw generator for power outages, disaster situations etc and think it would be easier to simply connect generator to main board rather than running off extension cords from generator as I had to in the last outage.

Any experiences? General cost if you've had it done? Easy to use? Thoughts around it providing "clean" power so can run PC etc?

Cheers.

wellygary

8315 posts

Uber Geek

#2217438 15-Apr-2019 14:07

Connecting an alternative source into existing grid connected wiring is a big can'o'worms.....

To be honest, it would probably be easier to get a bunch of separate wall outlets wired back to the GenSet, (independent of the mains wiring) then you can just replug the appliances when you have a failure...

its never going to be a auto switch over anyway as you have to go out and start up the Genny....

5KW @240V is ~20amps.... and I'm guessing that your grid supply is much larger than that, so you would be running a mains board with potentially significantly more load than supply....

Also how often does this happen?, and how much are you prepared to spend?,

but if you are serious go an find a sparky that does PV installs, as they will have experience in what you are looking to do...

DarthKermit

5346 posts

Uber Geek

Trusted

#2217440 15-Apr-2019 14:09

A UPS would provide nearly instant backup power from its battery to keep systems running. No generator could do that, even if it did have some kind of automatic startup system.

sootyandsweep

16 posts

Geek

#2217444 15-Apr-2019 14:15

That's some great thoughts thank you. I hadn't considered that it would only deliver so many amps. Doesn't happen enough to warrant major spend hence wanted to find out anything others have done. Independent wiring could be a good option as the last time I needed to power a water pump for bore and infinity ignition for gas hot water so I could at least shower. A nighttime power cut would need a couple of lights which could be delivered via lamp so a good thought for a couple of plugs around.

sootyandsweep

16 posts

Geek

#2217445 15-Apr-2019 14:17

DarthKermit:

A UPS would provide nearly instant backup power from its battery to keep systems running. No generator could do that, even if it did have some kind of automatic startup system.

Agree however it doesn't worry me about losing power and having to start up a generator, its more of a ease thing when power is out to not have to run extension cords from outside in through windows etc.

mdooher

Hmm, what to write...
1424 posts

Uber Geek

ID Verified

Trusted

Lifetime subscriber

#2217449 15-Apr-2019 14:22

Wiring in a manual transfer switch for a plug-in generator is actually a pretty simple job for a competent sparkey. (yes it can be complex but not usually)

Basically it goes between the meter and your main switch so you can get power either from the meter (network) or generator (yes of course there are variations depending on where you live)

I have done a few, and apart from requiring an inspection and a service request (if you need to get into the meter terminals) it isn't much different from any other job.

An auto changeover switch with load shedding and UPS integration however.... get out your cheque book

couple of Hundred for the switch/appliance inlet

an easy job maybe 3 hours

Inspection fee

Matthew

SirHumphreyAppleby

2844 posts

Uber Geek

#2217454 15-Apr-2019 14:32

I haven't made enquiries in to these products, but TradeTested is offering 3 phase Automatic Transfer Switches with generator control for $1299-1799 depending on capacity required. They mention battery charging in the specs, but I assume that's just to power the system. For a fully automatic system, you'd still require a self-starting generator and UPS.

I believe Victron has units which have everything built-in - battery charger, inverter, generator control and transfer switch, but when I looked in to the options a few years back it was several thousand for the basic model. Decided to defer until I build a house, so I'm watching this thread hoping some more cost-effective solutions will be mentioned.

Aredwood

3885 posts

Uber Geek

#2217681 15-Apr-2019 20:55

Check first that that generator actually outputs true 230V power. The cheaper units instead output 115 0 115V. Which works when you plug appliances in directly with extension cords. But connect such a generator into your house wiring. You will either destroy it. Or the outer case of the generator will be live at 115V to earth.

Sharesies kids

Free kids accounts - trade shares and funds (NZ, US) with Sharesies (affiliate link).

mclean

581 posts

Ultimate Geek

Subscriber

#2218033 16-Apr-2019 11:12

mdooher: Wiring in a manual transfer switch for a plug-in generator is actually a pretty simple job for a competent sparkey. (yes it can be complex but not usually)

Basically it goes between the meter and your main switch so you can get power either from the meter (network) or generator (yes of course there are variations depending on where you live)

A manual transfer switch has a centre-OFF position, so it can actually replace the main switch if you want.

Having a genset with less capacity than the main supply isn't an issue if the genset is properly protected. However you need to reduce the load (by turning things off in the house) before you switch the MTS to the generator position. It's probably best to turn everything off while you switch over and start the genset.

A battery emergency light over the switchboard and genset is a good idea.

One of the requirements for using a genset as an alternative supply is that it has to use the same earthing/bonding arrangement as the house. You may have to modify the wiring in the genset to make it work this way.

As mdooher says, you need a good sparky for this, one who's up to speed with NZS 3010.