Changeover switches reccomendations (and what do the regs say)

[jimseng]

Hello.
My electrician was questioning the regs regarding changeover switches as he has not fitted one to an inverter before. I intend to have two changeover switches, one to connect my grid DB to the load output of the inverter in the case of a long term power cut and one to connect the load DB to the grid in case of an inverter failure. I know others on here have done exactly this so I thought I would ask for recommendations as to what make/model of switch people feel is suitable. My inverter is a 10k single phase and the supply breakers will most likely be rated at 63 amp.

The electrician has always fitted large 3 position changeovers for large generator installations. His concern is whether there is a regulation that the changeover switch should have an off position, in other words a 3 position switch.

 
I was considering something that would be along the lines of the image below, din mounted in a neat box. rated at 125a. However this unit is £17 + vat which he thought sounded cheap and nasty.
It also seems to be a one or other position, not and on - off -on. Does anybody know if there is any reg or code of practice that prohibits this type of changeover for what I want to do?

Any particular units I should be looking at?

 

[JohnMo]

42 minutes ago, jimseng said:

output of the inverter

So is this an inverter that will run in Island mode, most don't 

[jimseng]

2 hours ago, JohnMo said:

So is this an inverter that will run in Island mode, most don't 

Yes. (It already is, not going to be on grid for half a year)

[Dillsue]

I've got 2 of those changeover switches, one in each of the main house consumer units. They let either of the CUs be fed from the grid or the backup output from the inverter. One is normally fed from the grid, the other normally fed from the inverter backup output.

 

I'm not aware of any regs that prevent that configuration but it's such a niche that I'm not sure those producing the regs will have detailed if and how they should be use?? 

[jimseng]

 

This Geya unit seems to be a 3 position switch. They seem very little money. Anyone got anything to say about quality or UK standards?

GYHO8 Transfer Switch 1P

[Marvin]

I have used 20+ time delay on off / relay switches from GEYA and found them all ok.

Sometimes the instructions have been a little hard to understand but maybe that's just me.

 

 

 

[Dillsue]

11 hours ago, jimseng said:

 

This Geya unit seems to be a 3 position switch. They seem very little money. Anyone got anything to say about quality or UK standards?

GYHO8 Transfer Switch 1P

I think that's a 2 position unit? The I and II show the 2 positions

[jimseng]

From the Geya web page:

"Modular manual changeover switches are a unique solution that has a three-stable position switch I-0-ll "

Hopefully I haven't mis-understood that, if so I am an even bigger idiot than I thought.

However I have found a Hager unit which I think ticks UK electricians boxes. It is twice the price but not crazy:

https://hager.com/uk/products/h/sf263-2-pole-changeoverswitch-63a-i-0-ii

[Dillsue]

I guess the Geya description trumps the symbol on the unit....a 0 printed on the unit would make it clearer.

 

If you are having the changeover switch in a separate enclosure to the CU then having the standard 2 pole main switch in the CU would remove the need for the changeover to have an OFF position?? If you need to pacify your spark by having an OFF position then the Geya or Hager units seem to do that.

 

I'm pretty sure all the units you've posted will fit in standard CUs so it might be neater to have a slightly larger CU and house the changeover switch in that rather than a separate enclosure??

[-rick-]

2 hours ago, Dillsue said:

I'm pretty sure all the units you've posted will fit in standard CUs so it might be neater to have a slightly larger CU and house the changeover switch in that rather than a separate enclosure??

 

Then you'd need to either use a matching brand/spec transfer switch that's certified for the same CU or have a sparky that's willing the do the risk assessment and put his/her name to the safety of the third party switch.

 

I'd guess a separate enclosure would be easier. Once you do that, there are multiple options of pre-packaged solutions available. More expensive sure, but all-in-one and likely easy to get the sparky comfortable with.

 

https://www.cef.co.uk/catalogue/products/1780374-63a-2p-surface-mounting-3-position-changeover-switch-ip65

[Dillsue]

1 hour ago, -rick- said:

 

Then you'd need to either use a matching brand/spec transfer switch that's certified for the same CU or have a sparky that's willing the do the risk assessment and put his/her name to the safety of the third party switch.

 

Given that the changeover switch is wholly cable connected and doesn't need busbar alignment/compatibility with the CU, what hazards would you envisage being on the sparks risk assessment if you used a different manufacturers unit??

Edited 16 hours ago by Dillsue

[-rick-]

Just now, Dillsue said:

Given that the changeover switch is wholly cable connected and doesn't need busbar alignment/compatibility with the CU, what hazards would you envisage being on the sparks risk assessment??

 

It's related to gaps surrounding the module. The regs tightened up the rules around what you can fit in a domestic CU and the effect is that most sparks won't want to fit anything that isn't certified by the manufacturer as compatible/suitable for use with that specific CU.

[jimseng]

Thanks for the responses. The electrician has already mentioned the matching brand to the CU issue but he is probably going to fit Hager stuff anyway as that seems to be his go to brand.