Pond Aerator Pump Protection

[dogfonos]

I have a pond aerator pump that plugs into mains electricity. In normal use, it draws 4 Watts, evidently. It wasn't supplied with a mains plug so I fitted one and installed the lowest rated mains fuse I had - 2 Amps. However, the instruction manual states:

"should be fused for a rated fault current of max. 30mA by means of a fault current protection device".

Maybe I'm misinterpreting this statement but I take that to mean either a 0.03 Amp fuse or MCB?!? They don't exist, do they? Maybe they mean an RCD? An explanation would be appreciated, thanks.

 

[ericmark]

Yes it means a RCD, is does measure current, it basic measures amps in and amps out and assumes if not equal must have gone to earth 0.03 amps (30 mA) is the standard size.

 

[EFLImpudence]

They apparently do mean an RCD but that is irrelevant to the fuse rating and the 30mA operating current of an RCD does not limit the fault current which will occur during a fault.

Fuses are to protect the cables so it depends on the cable rating.

However, that does not preclude using a fuse lower than that rating - 2A or the usual 3A will be fine.

 

[SFK]

Your Fuse Box (Cinsumer Unit) may already provie 30mA RCD protection.
Otherwise the following using your lower rated fuse:
https://www.screwfix.com/p/masterplug-13a-fused-plug-through-active-rcd-adaptor/63731
https://www.screwfix.com/p/masterplug-13a-unfused-plug-in-active-rcd-plug/44855

 

[JohnW2]

.... https://www.screwfix.com/p/masterplug-13a-fused-plug-through-active-rcd-adaptor/63731
https://www.screwfix.com/p/masterplug-13a-unfused-plug-in-active-rcd-plug/44855

Does the first of those really contain a fuse? If so, what on earth purpose does it serve?

Kind Regards, John

 

[SFK]

Does the first of those really contain a fuse?

John - made me look. :>
I have a JCB one to hand, and yes it has a fuse plate and a 13A fuse inside it.

what on earth purpose does it serve?

No idea. Perhaps to safeguard its internal wiring and incase someone plugs in a Chinise infused plugtop.

SFK

 

[JohnW2]

Does the first of those really contain a fuse? If so, what on earth purpose does it serve?

Photos show no evidence of a fuse (unless it's hidden on the bottom) - so what does "fused" in the name of the first one (but not the second, which is entitled "unfused") mean?

Kind Regards, John

 

[JohnW2]

Oh, I was looking at the wrong one - confusing 'cos the colours of the two (on Masterplug website) were the opposite of the Screwfix photos . So it does have a fuse. Very odd!

Kind Regards, John

 

[JohnW2]

... and the description of the unfused one (but not the fused one) includes ...

It is non-latching, therefore power needs to be reset at each use and it is ideal for home appliance spike protection.

Kind Regards, John

 

[EFLImpudence]

So it does have a fuse. Very odd!
View attachment 235401

Is that a flex outlet at the bottom - for wiring direct to the appliance and no socket on the other side?

 

[EFLImpudence]

Has Screwfix got the fused and unfused the wrong way round?

 

[JohnW2]

Is that a flex outlet at the bottom - for wiring direct to the appliance and no socket on the other side?

I'm doing well at getting confused and hence confusing everyone else. You're right - the fused one is hardwired and doesn't have a 'socket' to plug into. Whether the one depicted by Screwfix ("fused" AND with a socket outlet, described as a 'plug-through adapter) actyal exists or not, I don't know. The front of the fused one of which I recently posted the back view (showing the fuse) looks like this (no 'socket')
:

Kind Regards, John

 

[JohnW2]

Has Screwfix got the fused and unfused the wrong way round?

Yep, that's the answer.

All is now clear (no thanks to Screwfix), and the reason for the fuse is clear. Apologies for adding to the confusion!

Kind Regards, John

 

[SFK]

Just to add to the maddness - photos of my JCB 30mA RCD 'Socket' with a 13A fuse in the back.
Which brings us back to the question

Does the first of those really contain a fuse? If so, what on earth purpose does it serve?

 

[JohnW2]

Just to add to the maddness - photos of my JCB 30mA RCD 'Socket' with a 13A fuse in the back.
Which brings us back to the question ....

Quite. It really makes little sense - as you may well agree, the two suggestions you previously offered (as regards 'what on earth is the purpose of the fuse?') seem a little far-fetched - although I can't say that I can think of any better explanations!

If they were concerned about people plugging in "Chinese unfused plugs", that would be an argument for including fuses in all sockets (two in double ones)!

Kind Regards, John