MCB thingymajig

[mrsmelly]

Hi leecy peeps again.

Right so we are whimping out doing pretend boating in a marina on shorepower. We have a combi thingy ( Yes I know it would be seperates if it was me but it was fitted ) anyway missus last week tried running every leccy piece of kit known to man at once and there is a thin I think its an mcb? that is the first thing the umbilical is plugged in to on entering the boat and it tripped, no problem I reset it and all ok. Today she tried putting nineteen million amps through it and it tripped and on resetting nowt worked. Anyway twas easy to diagnose it were busted so I nips to Wickes to get another. The one I took of doesnt say what its spec is but looking online I think I a worked out its 16 amps. Anyway only one with a double switch thingy at Wickes is 100 amp. Now I needed to get out of a mess so I fitted it, two minute job and correct size physicaly so all now working again. Beyond this there are several other thingies that all look to be 16 ampy whatsits so although I am ensuring she doesnt overload the big thing how bad is it having a 100 amp thingy as first port of call for the umbilical  Yes I am going to get a smaller capacity one if I must which I should I suppose, I dont think though wickes or screwfix do the right thing ?

[ditchcrawler]

3 minutes ago, mrsmelly said:

Hi leecy peeps again.

Right so we are whimping out doing pretend boating in a marina on shorepower. We have a combi thingy ( Yes I know it would be seperates if it was me but it was fitted ) anyway missus last week tried running every leccy piece of kit known to man at once and there is a thin I think its an mcb? that is the first thing the umbilical is plugged in to on entering the boat and it tripped, no problem I reset it and all ok. Today she tried putting nineteen million amps through it and it tripped and on resetting nowt worked. Anyway twas easy to diagnose it were busted so I nips to Wickes to get another. The one I took of doesnt say what its spec is but looking online I think I a worked out its 16 amps. Anyway only one with a double switch thingy at Wickes is 100 amp. Now I needed to get out of a mess so I fitted it, two minute job and correct size physicaly so all now working again. Beyond this there are several other thingies that all look to be 16 ampy whatsits so although I am ensuring she doesnt overload the big thing how bad is it having a 100 amp thingy as first port of call for the umbilical  Yes I am going to get a smaller capacity one if I must which I should I suppose, I dont think though wickes or screwfix do the right thing ?

https://www.screwfix.com/p/bg-mcb-16a-b-type/35253#_=p

[mrsmelly]

Just now, ditchcrawler said:

https://www.screwfix.com/p/bg-mcb-16a-b-type/35253#_=p

Thanks old sport but its not one of those. It looks like that but it is twice as wide with wires going in top and bottom as in pos and neg bottom and pos and neg top. I cant do pictures or owt 

[AndrewIC]

A 100A thingy sounds like an isolation switch. A 16A thingy with two wires top and bottom sounds like an RCD. Take the remains of the dead thingy to a proper electrical place, if you have replaced an RCD with a plain switch then you have no protection from electric shock hazards.

[alan_fincher]

I think you talk of an RCD, like this?
 

https://www.screwfix.com/p/rcd-40a-30ma-double-pole-type-ac/52457

 

If so the Amps rating is simply the most it can pass, and I can't see it being an issue using one with a much higher overall rating than you need.

The key figure is not the overall Amps figure, but the milliamps necessary to cause it to trip if there is leakage to earth.

The normal value for the leakage current needed to trip them is 30 milliamps, and I'd be surprised if many are rated any different to that.  If it possible to get one that needs more than 30 mA to trip it, I certainly wouldn't use it though.  That current coud be flowing to earth through you, and 30 mA is already far more than needed to kill you.

[mrsmelly]

2 minutes ago, AndrewIC said:

A 100A thingy sounds like an isolation switch. A 16A thingy with two wires top and bottom sounds like an RCD. Take the remains of the dead thingy to a proper electrical place, if you have replaced an RCD with a plain switch then you have no protection from electric shock hazards.

Its a " Main switch 100 amp Double Pole isolator " 110555 thingy. It looks identical and fitted physicaly where the other thing was? 

[rusty69]

3 minutes ago, AndrewIC said:

if you have replaced an RCD with a plain switch then you have no protection from electric shock hazards.

Unless there is one in the shore bollard

[nicknorman]

No the 16A thingy is likely to be an MCB (jumped-up fuse). The 100A thing is likely to be an RCD. Did either of them have a trip button? That is a clue that it is an RCD.

1 minute ago, mrsmelly said:

Its a " Main switch 100 amp Double Pole isolator " 110555 thingy. It looks identical and fitted physicaly where the other thing was? 

If the other thing was labelled 16A then you have replaced it with the wrong thing, even if it looks similar.

[mrsmelly]

2 minutes ago, alan_fincher said:

I think you talk of an RCD, like this?
 

https://www.screwfix.com/p/rcd-40a-30ma-double-pole-type-ac/52457

 

If so the Amps rating is simply the most it can pass, and I can't see it being an issue using one with a much higher overall rating than you need.

The key figure is not the overall Amps figure, but the milliamps necessary to cause it to trip if there is leakage to earth.

The normal value for the leakage current needed to trip them is 30 milliamps, and I'd be surprised if many are rated any different to that.  If it possible to get one that needs more than 30 mA to trip it, I certainly wouldn't use it though.  That current coud be flowing to earth through you, and 30 mA is already far more than needed to kill you.

Thanks Alan. It doesnt have the test button thingy on it but all the other things in the consumer units onboard do so I am unsure realy what it is but I think then its probably ok 

[Guest]

1 minute ago, mrsmelly said:

Thanks Alan. It doesnt have the test button thingy on it but all the other things in the consumer units onboard do so I am unsure realy what it is but I think then its probably ok 

Sound like RCCBO units?

[alan_fincher]

How about a picture of the you(r other half) broke, and one you have put in to replace it?

As Nick says, if it is an RCD (residual current device), it should have a button to simulate testing it.  If the old one did, but the new one doesn't, I'd be concerned you are no longer fully protected by an RCD.

An RCD will be markd with the leakage current at which it is designd to trip, usually 30mA, and if what you removed was so marked then it was an RCD.  What goes back must also be an RCD, similarly marked.

[mrsmelly]

4 minutes ago, nicknorman said:

No the 16A thingy is likely to be an MCB (jumped-up fuse). The 100A thing is likely to be an RCD. Did either of them have a trip button? That is a clue that it is an RCD.

If the other thing was labelled 16A then you have replaced it with the wrong thing, even if it looks similar.

Kinell. I have just been on wickes site and ut in the search engine110555 and thats what I have fitted. It works and looks same as other with a swith up for on down for off?

[alan_fincher]

Pictures needed, I think!

[mrsmelly]

Just now, alan_fincher said:

Pictures needed, I think!

No hope Im afraid I havnt a clue how to do them. all the other things onboard after that thing have test buttons so I am wondering why this tripped in the first place? I will pick brains of some leccy person localy methinks 

[alan_fincher]

1 minute ago, mrsmelly said:

Kinell. I have just been on wickes site and ut in the search engine110555 and thats what I have fitted. It works and looks same as other with a swith up for on down for off?

No that's just a switch, definitely not an RCD.

http://www.wickes.co.uk/Wylex-Main-Switch-Double-Pole-Isolator---100A/p/110555

If what you removed was an RCD, this is not a safe replacement for it.

[mrsmelly]

Just now, alan_fincher said:

No that's just a switch, definitely not an RCD.

http://www.wickes.co.uk/Wylex-Main-Switch-Double-Pole-Isolator---100A/p/110555

If what you removed was an RCD, this is not a safe replacement for it.

Yes thats the one. Looks identical except for make to the one I removed. One I removed didnt have a test button or anything either so looks like this is just an isolater for the outside cable?

[matty40s]

That one is used for a large domestic oven or household immersion.

 

[alan_fincher]

4 minutes ago, mrsmelly said:

No hope Im afraid I havnt a clue how to do them. all the other things onboard after that thing have test buttons so I am wondering why this tripped in the first place? I will pick brains of some leccy person localy methinks 

The Wickes item you have posted details of I don't believe is capable of tripping, (unless you feed it LSD!).

It is just a switch.

If what you removed tripped, presumably for a good reason, then you have now replaced it with something that can't, which does not sound very safe to me at all.

(Unless I'm completely misunderstanding!)

Edited January 9, 2018 by alan_fincher

[matty40s]

quite often the 16a switches trip and when you try to push them back up, they dont click properly.

to correct this, you need to push the switch down completely and then push back up to make it work.

this may be what happened the second time with yours.

[mrsmelly]

1 minute ago, alan_fincher said:

The Wickes item you have posted details of I don't believe is capable of tripping, (unless you feed it LSD!).

It is just a switch.

If what you removed tripped, presumably for a good reason, then you have now replaced it with something that can't, which does not sound very safe to me at all.

(Unless I'm completely misunderstanding!)

Yes the old one tripped off but it looks identical. All others onboard have the trip test buttons, must look further 

[ditchcrawler]

Get a professional to look,what you are playing with can kill you. I am not trying to be alarmest

[alan_fincher]

2 minutes ago, mrsmelly said:

Yes thats the one. Looks identical except for make to the one I removed. One I removed didnt have a test button or anything either so looks like this is just an isolater for the outside cable?

But you said the one you removed tripped.

I don't believe this switch can.

So, I'm sorry, so they may look idntical, but I don't see how they possibly can be.

A simple switch can't "trip" it needs a human to push it.

[mrsmelly]

1 minute ago, matty40s said:

quite often the 16a switches trip and when you try to push them back up, they dont click properly.

to correct this, you need to push the switch down completely and then push back up to make it work.

this may be what happened the second time with yours.

No dood I tried all that its deffo stuffed and the new one has all back on again 

1 minute ago, ditchcrawler said:

Get a professional to look,what you are playing with can kill you. I am not trying to be alarmest

Yes. Meantime I will just make sure its only the missus that goes near it.

[ditchcrawler]

Replacing a 13 amp fuse in a plugtop with a piece of nail will work,but its not safe

[mrsmelly]

1 minute ago, alan_fincher said:

But you said the one you removed tripped.

I don't believe this switch can.

So, I'm sorry, so they may look idntical, but I don't see how they possibly can be.

A simple switch can't "trip" it needs a human to push it.

Deffo tripped. Did it last week so I reset it and did it today, weird innitt