What safety devices are there when using 240v via an inverter?

[Pausim]

My solution, having been guided by everyones comments is that I will use a camping lead with rcd protection when cooking outdoors!

Make sure it is a 2 pole RCD a single pole one may not provide any protection.

 

[DavidCh]

Providing you are just connecting to the sockets on the inverter, no. An RCD as we have previously discussed does nothing in this situation and the inverter will be internally protected from overload. Also, because you are in the UK with the best designed plugs and sockets in the world you have fuses in them

 

[Pausim]

Providing you are just connecting to the sockets on the inverter, no. An RCD as we have previously discussed does nothing in this situation and the inverter will be internally protected from overload. Also, because you are in the UK with the best designed plugs and sockets in the world you have fuses in them

If they were the best designed sockets and switches for this application they would not have single pole switches which can leave one of the supply wires live. They just create a false sense of security if the inverter is using out of phase 115V down both wires. Far safer to have no switch then people know the only safe way to isolate the appliance is to unplug it. Also applies to general continental use where polarity is not fixed.

 

[DavidCh]

I am not familar with the inverter but I would not have expected the sockets to have any switches on them. If you where going to wire in sockets with switches then you would have bonded the earth and neutral at the inverter and fitted an RCD in which case you would not get the 115v on each line as it now has an earth reference.

 

[autorouter]

Also, because you are in the UK with the best designed plugs and sockets in the world you have fuses in them

Yes, but single-pole fuses are not safe, so just make sure they are double-pole fuses.

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[Bessy765]

If I use 240v via the EHU, there are safety devices (RCD's I assume?) to offer protection against faults with the manufacturer installed consumer unit.

But what about when using 240v via a battery supply, when using appliances being fed via an inverter?

I know my inverter automatically switches off if I overload it, but what if a fault developed in the wiring or the appliance itself? Should I actually install a mini consumer unit with RCD's or arrange the wiring via a relay so that it auto switches and both the inverter and EHU feed everything via the consumer unit already installed?

autorouter
Raul
Hoovie

I already have the relay recommended to me on earlier threads and it makes sense to me to make it an auto changing setup, so that all 240v runs via the but I am a little unsure as to feeding all the 240v from just one socket on the inverter will suffice?

It's a generic 2000w/4000w inverter with two UK sockets, does that suggest each socket can supply 1000w or could just one socket provide up to 2000w ?

You should also take into account what size and type your batteries are. You might use around 26 amps @ 12 volt d.c. to produce 1 amp at 240 volts allowing for inverter inefficiencies and voltage drop. So 4000 w could mean in excess of 400 amps

 

[Trevor Wbm]

I know this is unhelpful, but have you considered a gas Cadac?

 

[MisterB]

You should also take into account what size and type your batteries are. You might use around 26 amps @ 12 volt d.c. to produce 1 amp at 240 volts allowing for inverter inefficiencies and voltage drop. So 4000 w could mean in excess of 400 amps

i have a 300ah fogstar lithium. my max draw would likely be if i have the microwave and kettle on at the same time or the induction hob and kettle - so i am pretty confident the Renogy 3000w (now on order!) will more than cover my useage.

 

[MisterB]

I know this is unhelpful, but have you considered a gas Cadac?

lol, its not unhelpful, i can actually see the funny side of your comment - on the basis that i do have a cadac, in fact i have several including the two burner model AND i also have the cadac trio power pack to supplement 'away' from the motorhome cooking !

 

[JockandRita]

I know this is unhelpful, but have you considered a gas Cadac?

i have a 300ah fogstar lithium. my max draw would likely be if i have the microwave and kettle on at the same time or the induction hob and kettle - so i am pretty confident the Renogy 3000w (now on order!) will more than cover my useage.

Way to go Dave, instead of all that poncing about with unnecessary expenditure and grief.

Cheers,

Jock.

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[DavidCh]

Yes, but single-pole fuses are not safe, so just make sure they are double-pole fuses.

From what? A fused plug is designed to blow the fuse if there is a current overload, or a short circuit. A fuse does not protect a person from electric shock.

 

[autorouter]

From what? A fused plug is designed to blow the fuse if there is a current overload, or a short circuit. A fuse does not protect a person from electric shock.

In the event of a fault or damage to the appliance, and the live and neutral were reversed, the fuse would blow but the majority of the wiring, and possible metal parts, would still be live. A double-pole breaker would isolate both poles, so the wiring would not be live. Are you saying that is an intentional feature of this 'best designed plug in the world'? Or is it a design problem?

 

[stevewagner]

Given that the three pin plug was designed for use in the UK it is an excellent design and fit for purpose, given that UK homes would only have reverse polarity if someone made an error during installation or additional electrical works. However a properly trained and skilled electrician would spot the fault as soon as he/she carried out effective testing with a calibrated instrument during and after installation.

 

[Pausim]

Given that the three pin plug was designed for use in the UK it is an excellent design and fit for purpose, given that UK homes would only have reverse polarity if someone made an error during installation or additional electrical works. However a properly trained and skilled electrician would spot the fault as soon as he/she carried out effective testing with a calibrated instrument during and after installation.

Yes but that doesn’t make it fit for purpose in a motorhome which is designed to travel around to places where polarity is not fixed or where inverters are frequently used with no guarantee concerning polarity. Nothing much can be done about plugs with built in fuses but everything else can be covered by only using 2 pole switching. Better no switch at all than one that might leave appliances live.

 

[autorouter]

Given that the three pin plug was designed for use in the UK it is an excellent design and fit for purpose

Those of us old enough will remember the original design, with the two fully metal live and neutral pins, which it was possible to touch with your fingers as it went into the socket. The bodge of adding insulation to the first half of the pin is a permanent reminder of just how good the designers were. In fact it's so good that replacing the fuse with a nail would actually make it safer in a motorhome situation

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[Pausim]

Am I right in thinking that this UK obsession with fused plugs and polarity arises from our use of ring mains? Most other parts of the world don’t have ring mains and seem to have radial wiring and mains panel breakers that are matched to the wiring. This takes care of overload without having the need for extra plug/spur fuses. From my unprofessional viewpoint having double insulation and wiring protected by the mains panel seems to make more sense than individual fuses scattered throughout a building.

 

[MisterB]

its been a long time since i revisited this thread and ive learned a lot AND spent a lot. i eventually invested in a Renogy 3000w inverter and have been more than happy with the install. i added surge protection and a double pole rcd prior to the surge protection.
i havent however yet added the external 240v socket, but its probably next on my list and its a long list which only seems to get longer every time i see what someone else has added or the way in which they make best use of their 'stuff'. i have been using a camping type extension lead with its own in built rcds. That allows me to split the incoming EHU just prior to it entering the moho if on EHU or just plug it into a socket supplied by the inverter (and by ehu via the renogy inverters pass through facility) using a standard uk to caravan fly lead.

so, my advice is that if anyone else is thinking of going down the same path ask as many questions as you can and be prepared to change your 'chosen path' based on the information/suggestions that you receive, it certainly worked out for me!