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Good quality change over switch.


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In my opinion whatever you buy these days has some cheap chinese tat incorporated within it if not completely manufactured in china and a known brand name stuck on. This, in my experience, applies especially to tech and electronics.

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I use one of these: https://www.midlandchandlers.co.uk/products/sterling-16a-manual-crossover-switch-vl-466

 

OFF + 3 inputs.  In my case, (1) shoreline or generator, (2) inverter, (3) travel pack.

 

Sold as Sterling but manufactured by a well known switch company.

 

Fork crimps make it easier to wire up.

 

Or you can buy a panel assembly https://www.midlandchandlers.co.uk/products/2-way-ac-shoreline-invert-selector-panel-vs-110

Edited by GRLMK38
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Whatever switch you buy, check that it says it is a Break Before Make type, not a Make Before Break. This helps ensure that at no time is the inverter connected to the shore power, or generator, even momentarily. May need going in to the tech spec details to be sure.

Jen

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31 minutes ago, Jen-in-Wellies said:

Whatever switch you buy, check that it says it is a Break Before Make type, not a Make Before Break. This helps ensure that at no time is the inverter connected to the shore power, or generator, even momentarily. May need going in to the tech spec details to be sure.

Jen

One that has the 'off' position in the middle will achieve this. One that has the 'off' at one side may or may not.

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1 hour ago, David Mack said:

One that has the 'off' position in the middle will achieve this. One that has the 'off' at one side may or may not.

This is a good shout, as was @Jen-in-Wellies original suggestion. Of course, it would still be wise to shut off before changing over and, because you're doing so, you don't necessarily need to fork out the extra cash for the high quality switchgear with contacts that can stand the resultant arcing caused by switching under load.

 

My inexpensive 1 - 0 - 2 changeover switch has had no trouble coping and I'd tell you what make and model it was if I could remember, but I'm struggling to remember what my boat looks like right now!

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Thanks all he's going with an ABB three position 25amp amp one. Centre position off, 1 and 2 to the left and right respectively.

 

Not the cheapest but the quality seems excellent.

 

He's saved a bit on the deferred items so is happy to spend a bit more.

 

Thanks again.

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A reputable marine electrician fitted a fail safe method to our boat which means that we cannot have the inverter and shore power connected at the same time. He terminated the feed from the inverter and shore power in seperate 3pin sockets. We then have the feed to the 230v circuit terminating in a 3pin plug which has to be physically put into the appropriate socket. We find that this works for us. If we do change the source of 230v power we just have to remember to move the plug.

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8 minutes ago, Richard T said:

A reputable marine electrician fitted a fail safe method to our boat which means that we cannot have the inverter and shore power connected at the same time. He terminated the feed from the inverter and shore power in seperate 3pin sockets. We then have the feed to the 230v circuit terminating in a 3pin plug which has to be physically put into the appropriate socket. We find that this works for us. If we do change the source of 230v power we just have to remember to move the plug.

We have exactly the same arrangement.

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If separation of manual switching between off- shore -inverter (or shore- off- inverter) is such a critical safety factor, then how is it achieved during auto switching in combis? I don't have a combi but wondered how they safely separate the power sources when no manual switching is involved?

 

My mains selecter switch is just a rotary cam type switch which has shore next to inverter as fitted to thousands of other boats. Is that dangerous? I've been living with it for nearly 16 years and it's never blown up the inverter. Is it likely to at some point? Have any of the thousands of other boats with similar switches fitted had this problem over the last 20 years or so? It's a genuine question as I've never heard of it happening. So is this more of a theoretical risk rather than an actual one or should I be looking to get someone in to change it?

Edited by blackrose
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4 hours ago, blackrose said:

If separation of manual switching between off- shore -inverter (or shore- off- inverter) is such a critical safety factor, then how is it achieved during auto switching in combis? I don't have a combi but wondered how they safely separate the power sources when no manual switching is involved?

 

My mains selecter switch is just a rotary cam type switch which has shore next to inverter as fitted to thousands of other boats. Is that dangerous? I've been living with it for nearly 16 years and it's never blown up the inverter. Is it likely to at some point? Have any of the thousands of other boats with similar switches fitted had this problem over the last 20 years or so? It's a genuine question as I've never heard of it happening. So is this more of a theoretical risk rather than an actual one or should I be looking to get someone in to change it?

 

If you have not suffered magic expensive smoke then your switch must be break before make so it fine until such time as the something internal breaks and manages to short out some arts but that would be true of any form of relay or switch.

 

The relays involved with auto switching are break before make (most relays are) and the input that is normally isolated by the relay contacts is fed to the relay coil. When that input is energised the coil moves the contacts breaking one input and then making the other. When the normally isolated input (the one now connected by the relay) is turned off/unplugged  the relay coil id de-energised, so the contacts open on that input and then make on the other set of contacts.

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4 hours ago, blackrose said:

If separation of manual switching between off- shore -inverter (or shore- off- inverter) is such a critical safety factor, then how is it achieved during auto switching in combis? I don't have a combi but wondered how they safely separate the power sources when no manual switching is involved?

 

Feeding two phases done a single phase line is to be avoided - as is the even-more-safety-critical issue of grabbing different phases in each hand.

 

The washing (and drying) machine did not run on the travel power alternator; presumably the MSW wave form was too ragged.  So, I converted it to a two-phase appliance with electronic side running from the PSW inverter and the heater elements from the travel power.  I was correctly advised of the dangers of two phases in close proximity - but felt that it was not a great deal different from the manually switched  shoreline/inverter or the auto switching in a combi.

 

I put several stickers around the machine to remind myself and, before selling the boat, converted it back to standard.   I took the view that it was an acceptable arrangement all the time it was properly understood - but did not wish to take the chance that a subsequent owner did not appreciate the implications.

 

 

 

 

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7 hours ago, blackrose said:

If separation of manual switching between off- shore -inverter (or shore- off- inverter) is such a critical safety factor, then how is it achieved during auto switching in combis? I don't have a combi but wondered how they safely separate the power sources when no manual switching is involved?

 

My mains selecter switch is just a rotary cam type switch which has shore next to inverter as fitted to thousands of other boats. Is that dangerous? I've been living with it for nearly 16 years and it's never blown up the inverter. Is it likely to at some point? Have any of the thousands of other boats with similar switches fitted had this problem over the last 20 years or so? It's a genuine question as I've never heard of it happening. So is this more of a theoretical risk rather than an actual one or should I be looking to get someone in to change it?

 

With a combi, the inverter part monitors the mains waveform and adjusts its output until it is in synchronisation with it.

 

When in sync the switching can be undertaken "make before break" without resulting in explosion, fuse blowing or magic smoke being emitted.

 

With a seperate inverter, it is not possible to ensure the supplies are in sync, because you cannot manually alter the inveter frequency, hence it is essential to use "break before make" switching.

Edited by cuthound
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5 hours ago, Tony Brooks said:

 

If you have not suffered magic expensive smoke then your switch must be break before make so it fine until such time as the something internal breaks and manages to short out some arts but that would be true of any form of relay or switch.

 

 

 

This is the sort of thing I have. I guess it mush be cheap Chinese tatt?

 

Mains-240v-power-selector-switch-16amp-2-pole-3-way-PSS116

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