2 Position Change Over Switch

[VonR]

My main business is standby generator installation. I am always on the lookout for neatly packaged changeover switches for use in tight places.

A number of reputable suppliers are packaging the device shown in the pic into compact plastic or stell enclosures.

The switch itself is 2-pole, 2 position - i.e., no central 'off'.

Reg 551.6.1 (iii) clearly states the requirement for 'A three-position break-before-make changeover switch' I can't get a clear answer from suppliers if the mechanism is at least compliant with the 'break-before-make' part though one does say in their advert 'not to be used under load' - which sounds like a dangerous game if I am to entrust that policy to my customers.

I have ordered one for evaluation. Suppose, I could test standalone mode by connecting a couple of lamps to the 'Mains' & 'Generator' connectors and then introducing a power source to the consumer unit terminals. Then check that all lamps are off in mid position.

Any thoughts about the legitimacy of this device?

Thanks,

Ian

 

[ProDave]

The only 3 position break before make changeover switches I have ever seen, have been rotary switches.

 

[KNB]

Reg 551.6.1 (iii) clearly states the requirement for 'A three-position break-before-make changeover switch' I can't get a clear answer from suppliers if the mechanism is at least compliant with the 'break-before-make' part though one does say in their advert 'not to be used under load' - which sounds like a dangerous game if I am to entrust that policy to my customers.

If the manufacturers do not recommend the device to be used under load then it does not suit your requirements as your circuits are most likely to be under load at time of change over. Unless your clients are prepared or advised to shut every thing down before bringing a genset online and then powering everything up again after change over of supplies. And then the same agian after mains power is restored.

 

[KNB]

The only 3 position break before make changeover switches I have ever seen, have been rotary switches.

You can get hand - off - auto switches that are board mount and look just like MCB's but they are certainly not for this sort of application. We use them in control gear for amenity and street lighting circuits.

 

[VonR]

In fact, the one I ordered for evaluation arrived this morning. There is definitely a sort of half-way house position with both generator and mains circuits disconnected - so seems to comply with 'break before make'. However, the switch mechanism is so stiff that the user most likely will snap the whole enclosure off the wall - so I'm not going to use it.

 

[NozSpark]

Try Katco, I've had one off them before for a RV that I converted

 

[kme]

That is more like a "rec4", with a dual busbar attached - The sort of thing that was suggested for isolation of properties with dual supply (eg grid & PV).

But I`d say it was an isolator - and certainly not a "changover switch"

Rotary is the only thing I`d be looking at for that.

 

[SLIPSHOD & SLAPDASH]

How can the switch pictured be a changeover when it only has 2 sets of terminals ?

 

[KNB]

How can the switch pictured be a changeover when it only has 2 sets of terminals ?

If you look closely at the picture it's actually got 4 sets of terminals. 2 side be side top and 2 side by side bottom. Strange set up and I personally would use an on/off/on switch instead of this.