Wiring external pond pump.

[CaptainJack88]

I just wanted to double check my workings here.

I've bought a pond pump which comes without a plug on the end.
In the instructions it says that it must go through a DP fused spur with a min contact gap of 3mm (fitted with a 3 or 5a fuse), and a 10mA or 30mA RCD must be fitted to the supply.

To check, if I run it through this fused spur (need to check it is DP)
https://www.amazon.co.uk/gp/product/B006GAI2LM/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

then wire a plug with a 3 or 5a fuse into the spur and plug it into:
https://www.amazon.co.uk/Masterplug...8&qid=1473175540&sr=8-1&keywords=external+rcd

Would that be sufficient, or since I have direct access to the socket as its right next to the spur, can I simply put a plug on the end with a 5a fuse and straight into the socket above?

 

[JohnW2]

It sounds as if you should wire the pump's cable directly into the FCU ('fused spur') (with a 3A or 5A fuse in it), rather than via a plug/socket. As far as I am aware, all FCUs available today are DP.

Kind Regards, John

 

[CaptainJack88]

It sounds as if you should wire the pump's cable directly into the FCU ('fused spur') (with a 3A or 5A fuse in it), rather than via a plug/socket. As far as I am aware, all FCUs available today are DP.

Kind Regards, John

I think I have completely mis-interpreted what the instructions say.

The 10mA or 30A RCD is on my consumer unit for the ring the plugs are on as it is behind a 80A RCCB with a 30mA switch:

That means I can go straight into a 5A fused spur connected directly to the ring?

 

[winston1]

If you use a FCU you don't need a plug and socket. If you use a plug and socket you don't need a FCU. If you circuit is already RCD protected in the CU or elsewhere you don't need another in a socket.

 

[ericmark]

The 3A fuse can be in the plug, or in a FCU, or anywhere else, it does not need to be doubled up. The same with the RCD again it does not need to be doubled up, so if there is a RCD in the consumer unit then no need for another, if not in consumer unit then using a RCD FCU, or a RCD socket, or a RCD plug all do the same no need to double up.

There is may be a slight advantage to using a 10 mA RCD as well as the 30 mA RCD in the consumer unit, as if slowly the pump gets worse then it will take out the 10 mA before the 30 mA RCD, but if there is a quick fault like spade into cable, then likely will take out both together anyway.

The double pole thing is standard with most switches on FCU, but not always with sockets, however the main reason for double pole is so an earth to neutral fault is removed when switched off, and with a plug and socket you can unplug anyway so not really a problem.

In the consumer unit a RCD or RCBO will be passive or latched that is after a power cut it will remain in and does not need resetting. When the RCD is used away from the consumer unit then the voltage may drop under fault conditions to a point where the RCD could fail to work, so before fitting a passive or latched RCD one has to measure the loop impedance and ensure if there is a fault the fuse will blow before a fault causes the volts to drop below the point where the RCD will work. So away from the consumer unit it is normal to fit an active or non latched RCD. So if the voltage drops due to a fault it will fail safe and disconnect. The exception is where loss of power could cause real problems like with a supply to fridge or freezer. You may feel lost of water pump would kill fish before you find out it has failed so it needs a passive or latched, but normally an active or non latched is used. In real terms the loop impedance should always be tested and so you should never "NEED" an active or non latched RCD, but often DIY people don't measure the loop impedance so the fail safe option is used.

I would use a RCD FCU inside the house supplying a socket outside where there is not RCBO or RCD in the consumer unit, then you can have as many sockets as you want, all RCD protected.

 

[EFLImpudence]

It's not 30A; it's 0.030A - 30mA

 

[ericmark]

Sorry my reply written before the extra info, you do not need a RCD, as said unless you want multi-sockets outside no need for FCU. Either one or the other. The FCU is often used when tapping into a ring, as then you can add as many sockets as you like, other wise only one socket spurred from a ring final.

 

[JohnW2]

I think I have completely mis-interpreted what the instructions say. ... The 10mA or 30A RCD is on my consumer unit for the ring the plugs are on as it is behind a 80A RCCB with a 30mA switch:

Indeed.

That means I can go straight into a 5A fused spur connected directly to the ring?

Exactly.

Kind Regards, John

 

[CaptainJack88]

Is there an alternative to these glands. I've watched a million videos and despite trying for days, I cannot get the gland over the armour at all.

Simply put, it just doesn't connect

 

[JohnW2]

Is there an alternative to these glands. I've watched a million videos and despite trying for days, I cannot get the gland over the armour at all. Simply put, it just doesn't connect

What glands and what armour? - I don't think you have mentioned armoured cable before.

Kind Regards, John

 

[CaptainJack88]

What glands and what armour? - I don't think you have mentioned armoured cable before.

Kind Regards, John

It might have been in a different post. Hard to see on mobile.

It's 2.5mm armoured and a 20S gland. I can't even get the olive onto the bottom part of the tapered bit with the armour on it.

Unless they're just poorly made glands, it seems pretty impossible

 

[JohnW2]

It's 2.5mm armoured and a 20S gland. I can't even get the olive onto the bottom part of the tapered bit with the armour on it. Unless they're just poorly made glands, it seems pretty impossible

That should be the right size gland. Are you sure you've studied the videos etc. carefully enough? I'm not sure what you mean by the 'olive'. The inner parts of the cable (without armour) should go through that tapered (and knurled) bit, and then, after the armour strands have been cut suitably short, the back nut should go over the armour strands, compressing them against that tapered bit as the nut is tightened.

Kind Regards, John

 

[flameport]

I can't even get the olive onto the bottom part of the tapered bit with the armour on it.

The olive is tapered and only fits one way.

 

[JohnW2]

The olive is tapered and only fits one way.

What's this 'olive' that you're both talking about? As I wrote above, the back nut surely screws directly onto the body of the gland, with nothing (other than the armour) in between?

Kind Regards, John

 

[CaptainJack88]

What's this 'olive' that you're both talking about? As I wrote above, the back nut surely screws directly onto the body of the gland, with nothing (other than the armour) in between?

Kind Regards, John

Theres and olive inside the back nut that compresses against the steel when it's tightened.

I'll have to take another look but I'm sure it's so the correct way around