Can't connect the SWA cable. Practical help please.

[SteamyTea]

1 minute ago, Nickfromwales said:

These are usually geared down to hell, so next to nothing for start up loads/shunt resistance. Was DC on the last few I installed (SELV).

Instantaneous current is infinite.

It is more the nature of inductors, rather than the size of the load. Why we have capacitor start and run. Charge the capacitor first, then dump the coulombs into the inductive load.

This is often done with electronic control now.

AC or DC, makes no difference, just something to be aware of.

[saveasteading]

Basics question.

I turned off the circuit yesterday at the local switch in the house, and the relevant  circuit  at the consumer unit... I think it only supplies this one cable.

 

I disconnected the box to change to a better one. That went well, and the metal gland is solid.

No sparks or drama from the now exposed cable.

Meanwhile, the primary rcd tripped in the house.

How can that happen if the power is off?  

[SteamyTea]

19 minutes ago, saveasteading said:

Meanwhile, the primary rcd tripped in the house.

How can that happen if the power is off?  

Purely guessing here, but it it a safety feature of that RCD i.e. double isolation.

Or it could be that some stray current from something in the house i.e. a capacitor in a charging circuit, put enough juice down the line.  I think RCDs are omnidirectional, but as I said, guessing here.

[Nickfromwales]

42 minutes ago, saveasteading said:

Basics question.

I turned off the circuit yesterday at the local switch in the house, and the relevant  circuit  at the consumer unit... I think it only supplies this one cable.

 

I disconnected the box to change to a better one. That went well, and the metal gland is solid.

No sparks or drama from the now exposed cable.

Meanwhile, the primary rcd tripped in the house.

How can that happen if the power is off?  

Neutral to earth got shorted. 
 

Unless you’re off an RCBO the phase to earth imbalance will trigger the earth protective device (30ma) but also will happen in the event of a neutral to earth ‘short’. 

 

An earth trip utilises a coil that is connected across L and N, and when in normal play the difference between those is zero. If you touch a live wire and start dumping some of that potential through your body, to earth, then the sum of that discharge is apparent across the L and N, so (roughly speaking) if you drew down >30ma then >30ma of current would flow through the coil. That would trigger the device so it ‘trips’. 
 

If you connect neutral to earth the floating potential in these cables (from EMF) does the opposite, and energises that coil, again causing a trip. 

[saveasteading]

so should i turn off that rcd, and/or the one in  the consumer unit, before doing any more?

 

I have stupidly forgotten to put the cable through the hockey stick.   So  not a lot achieved!

If it was a straight pipe i might slice the length and insert the cable, but that wont work with the bend.

 

[Nickfromwales]

9 minutes ago, saveasteading said:

so should i turn off that rcd, and/or the one in  the consumer unit, before doing any more?

 

I have stupidly forgotten to put the cable through the hockey stick.   So  not a lot achieved!

If it was a straight pipe i might slice the length and insert the cable, but that wont work with the bend.

 

You can switch it off, or just tape over the earth whilst you’re pulling this in, just so none of the dead conductors can touch. That includes preventing the neutral hitting an earth connection/tag. 
 

That’s doable if you want minimal disruption. 

[saveasteading]

That's so simple and now seems obvious. Ta.

No brilliant idea on the hockey stick. It's all training for me I tell myself.

[SteamyTea]

5 hours ago, saveasteading said:

So  not a lot achieved

 

4 hours ago, saveasteading said:

It's all training for me I tell myself

Could you have learnt about it any other way.

Probably not, so a lot achieved.

[Kelvin]

5 hours ago, saveasteading said:

That's so simple and now seems obvious. Ta.

No brilliant idea on the hockey stick. It's all training for me I tell myself.

Undo what you’ve done and pull it through. Once it’s done it’ll be done for good. The hockey sticks are quite thick plastic (well the black 38mm one is) so would be hard to cut its length and then get the cable in. It would likely take as long as just doing it properly. If it’s any consolation I spent a day digging a trench and laying some duct to pull an Ethernet cable through. Very pleased with myself but it was hard work as I needed to use my concrete breaker to get through some large stones. All for nothing as the PV and battery storage didn’t need any CT clamps at the meter. 

[Onoff]

1 hour ago, Kelvin said:

If it’s any consolation I spent a day digging a trench and laying some duct to pull an Ethernet cable through. Very pleased with myself but it was hard work as I needed to use my concrete breaker to get through some large stones.

 

I've got to dig a 24m trench at the moment. Mulling buying a Chinese digger. 

[Kelvin]

23 minutes ago, Onoff said:

 

I've got to dig a 24m trench at the moment. Mulling buying a Chinese digger. 

I dug a 23m trench for our electrical cable by hand. I ought to have hired a digger but I only decided that at the half way point so decided to keep digging. It’s why I have a concrete breaker. I powered it from our electric car parked on the verge of the field with a long extension lead. 

[saveasteading]

On 28/07/2025 at 23:13, Kelvin said:

powered it from our electric car parked on the verge of the field with a long extension lead. 

I'd no idea this was possible. Is that common practice? 

[Kelvin]

5 hours ago, saveasteading said:

I'd no idea this was possible. Is that common practice? 

Becoming more common for EVs to do vehicle to load. We have an Ioniq 5 which can output 3.6kW which is at the higher end of what is available just now. It has a 3 pin plug inside and an adapter for outside. We powered some things in the house from the car for a while too. If also saved two days of building when there was a power cut and the guys building the wall had an electric mixer. 

 

It’s been handy camping as we have a portable induction hob and electric kettle. 

[saveasteading]

Thanks Hubbers. That is now working.

All I've done differently is cut some more old cable off and fed it straight (no bending) into an interim box, thence connecting the 2 boxes with a new and short length of T&E.

Hoorah the gate works.

I had 3 more occasions of the rcd tripping. "Obviously" with my new knowledge, when cutting the cable.  Twice more I expect through touching earth to something even when I thought I had shrouded the wires.

 

The problem appears to be as @ProDave suggested. Either from bending the old cable or at a fault in it.

Perhaps this taped connection!!! It's amazing it lasted as long as it did but it was invisible under 10 coats of gloss.

 

I've also decided that I don't like lever connectors. What a pain. The  wire has to be dead straight, and stranded cable is a pain too.... I know: it needs an end crimp.

[Onoff]

15 minutes ago, saveasteading said:

I've also decided that I don't like lever connectors. What a pain. The  wire has to be dead straight, and stranded cable is a pain too.... I know: it needs an end crimp.

 

Just squeeze it straight with a pair of pliers. 

[SteamyTea]

1 hour ago, Kelvin said:

We have have an Ioniq 5 which can output 3.6kW

 

1 hour ago, Kelvin said:

It’s been handy camping as we have a portable induction hob and electric kettle

Spend another £50k on another one and you could run a small shower.

Or just stay in a hotel.

[Kelvin]

37 minutes ago, SteamyTea said:

 

Spend another £50k on another one and you could run a small shower.

Or just stay in a hotel.

We like camping the fact you can run all the electrics from it rather than packing gas stoves etc  is an added bonus. 

[SteamyTea]

1 minute ago, Kelvin said:

We like camping the fact you can run all the electrics from it rather than packing gas stoves etc

When I go walking, my whole world is on my back.

Total mass, before food and water, is 7.5 kg. 10 kg with food and water.

I really should get a campervan, that way I can have a shower, rather than a dip in a cold stream.

[Kelvin]

We do a lot of Munro climbing and carry all our stuff for those trips. However we also like to go from place to place and always have our two dogs with us and bikes so the car is necessary. Other half would like a campervan but I can’t justify the cost and we’d need to flog one or other of the cars.

[Nickfromwales]

5 hours ago, saveasteading said:

I've also decided that I don't like lever connectors. What a pain. The  wire has to be dead straight, and stranded cable is a pain too.... I know: it needs an end crimp.

You sir, have CLEARLY not made off enough choc blocks in your time to appreciate the 19th wonder of the world, the lever connector.

 

I suggest you go and kneel on some pencils for such blasphemy, and repent.

[Nickfromwales]

Oh, and you only use end crimps (aka bootlace ferules) with screw down connectors such as.....choc blocks. Stranded cable just gets a twist to straighten it up.

[saveasteading]

1 hour ago, Nickfromwales said:

CLEARLY not made off enough choc blocks in your time

I used waco once then got a sparky to do the clever bit.   He removed and changed them all.

Then these as above this time. I think they are a bit small for the stranded  armoured cable.

I couldn't decide if I had to lift the lever or is that only for removal... holding that up was a nuisance.

 

I will practice tomorrow and maybe get the hang of it.

[Nickfromwales]

11 minutes ago, saveasteading said:

I couldn't decide if I had to lift the lever or is that only for removal... holding that up was a nuisance.

 

I will practice tomorrow and maybe get the hang of it.

Ok. Hold the press, ffs. 
 

With a Wago, not his budget 2nd cousin, you lift the lever and it stays there.
 

Then you insert the cable, viewing through the clear body to confirm that had arrived safely to the required insert depth, and THEN, you flick the lever over. 
 

Just so I can sleep tonight, what bit is the clever bit that the sparky did….?
 

 

[Kelvin]

B&Q sell the cheap copies. I got some for free and didn’t like them so have stuck Wago. 

[Onoff]

5 hours ago, Nickfromwales said:

Ok. Hold the press, ffs. 
 

With a Wago, not his budget 2nd cousin, you lift the lever and it stays there.
 

Then you insert the cable, viewing through the clear body to confirm that had arrived safely to the required insert depth, and THEN, you flick the lever over. 
 

Just so I can sleep tonight, what bit is the clever bit that the sparky did….?
 

 

 

Well...first you remove the wire insulation to the depth indicated on the back of WAGO...

 

😉