Creating non RCD socket outlet in a split load Installation

[kwikfix328]

I would like to have a single Non RCD protected socket in my house. This will be use purely for testing purposes, predominantly periodic testing of RCD plug type adaptors.
All of the socket outlets in my household are currently RCD protected from a split load CU.

I do have 3x Non RCD protected circuits, namely:

Power supply to shed ( terminated at the shed with an RCD 'Garage' CU).
Upstairs lighting circuit
Downstairs lighting circuit.

I have two (blanked) spare ways on the non RCD side of the main CU.

Obviosly the easiest and most straightforward method is to fit a new MCB and create a short radial circuit with a single surface mount socket outlet at the end, this socket would be located right next to the main CU in the electrical cupboard.

Any other safe and practical suggestions ?
Can i use any of the existing cicuits or MCB's ?

 

[Spark123]

I'd just stick a new MCB in and a short radial to the socket. Is it likely to be used to supply portable equipment outdoors? If so, label it not suitable for this purpose.
In what context do you mean testing plug in adaptors? Using a proper RCD tester instrument?

 

[kwikfix328]

I'd just stick a new MCB in and a short radial to the socket. Is it likely to be used to supply portable equipment outdoors? If so, label it not suitable for this purpose.

New MCB & Short radial does seem like the most 'proper' option.

This won't be getting used for portable or outside equpment . It will be purely used as a test socket.

In what context do you mean testing plug in adaptors? Using a proper RCD tester instrument?

Yeah, I picked up a new Megger RCD320 real cheap off e-bay.

The tools

• kwikfix328
• 6 May 2008
• 1

Althogh I'm not a domestic electrician, I am a fully qualified Commercial Aircraft electrician...

I then thought sod it and bought a Continuity/Ins checker and Loop tester too. They are slightly older models but still in GWO but just a few weeks out of cal.

I will use the RCD tester regularly and so to the Continuity/Insulation tester - i will probably keep this at work in fact as our old analogue Megger is older than Jesus , but gets used all the time. Probably use it on my cars too as i do a lot of DIY on them.

Not too sure about the EFLI tester though, I think I got kinda carried away a little when i bought that . I don't intend doing, (or getting done) any more electrical work on my house in the forseable future. All the jobs i wanted done are now done ( power to the shed, new lights in the loft and new RCD split load CU fitted).

OK then another question if you don't mind. Once EFLI / PSCC has been checked and verified to be within acceptable limits if an installation isn't modified in any way are they likely to change, and is this the sort of thing that is checked periodically ?
Obviously I know that until recently neither have been checked in the previous 8 years that I've lived in this house and i also doubt that they've ever been checked by the previous owners since build in 1987 either...

 

[Spark123]

To do installation work you need all 3 instruments. Not 100% sure on why you would use a megger on a car!! One thing for sure, I wouldn't be putting one anywhere near an expensive ECU!
The EFLI and PFC is checked as part of a PIR. They can change if a cable is degrading. You should also conduct an EFLI test prior to conducting an RCD test.

 

[plugwash]

BTW if you want to test a RCD when there are other RCDs upstream you can connect the testers earth lead to the incoming neutral.

 

[kwikfix328]

To do installation work you need all 3 instruments. Not 100% sure on why you would use a megger on a car!! One thing for sure, I wouldn't be putting one anywhere near an expensive ECU!
The EFLI and PFC is checked as part of a PIR. They can change if a cable is degrading. You should also conduct an EFLI test prior to conducting an RCD test.

OK I guess I'll keep a hold of it.

I've only tried the Non tripping auto test with the moulded plug test lead so far ( got a reading of 0.2 Ohms ? ) . Need to do a bit more reading before i go any further.

I certainly wouldn't try to megger a suspect wire if it had any black boxes on the end in the same way that I'd never megger a wire in a house unless all equipment was unplugged.
Houses, factories, Planes , trains and automobiles, the principles are all the same, wiring insulation gets damaged and breaks down causing faults. If that wires lives in a hostile envoironment , getting flexed and vibrated then just add water and you got yourself a fault.
A continuity/insulation tester can be used anywhere, although admittedly I normally start of on the 50 volt setting at work most of 'my' circuits are 28 vdc, ( with momentary 1600+ Amp peaks though ).

 

[Spark123]

I normally only use a fluke 73 multimeter my car!

 

[baldelectrician]

I would suggest a seperate circuit put through a key switch (MK Fish Key type) and suitably labelled.

If you want you could use a double grid plate with a key AND a momentary push to make 20A DP switch in series. Then you could only have power when both the key switch and the push button is operated.

 

[ban-all-sheds]

That's verging on paranoia..

 

[kwikfix328]

I normally only use a fluke 73 multimeter my car!

We have been using a Fluke 71 or 73 for at least 8 years that i know of almost every single shift at work, it's been dropped more times than a whores drawers & still on the original set of test leads too.

A brand that you can trust.

I'll admit that i too use a multi meter on my car , but its nice to have some choice if i need it

 

[Spark123]

I'm afraid I have broken a few sets of leads
I'm forever unplugging the leads on my fluke (77) at work swopping from V to mA, I tend to keep them stored in the voltage configuration.
I have also managed to shut it down my own fluke 73 on a high frequency circuit before . It fired up again but I lose a little bit of confidence in something when this happens.

 

[kwikfix328]

I decided to fit a very short 4mm T&E radial connected to its own dedicted B16 MCB at one end and a standard MK socket outlet at the other.

With the MCB selected off, a kiddy proof socket blank fitted, and a couple of warning labels stuck on, plus the fact that the socket is near the floor in the electrical cupboard hopefully folk will get the message not to touch.

I will keep an RCD plug adaptor nearby just incase anyway, i can use this as my Calibration checker too, which was mostly the idea behind this thread anyway.

Tst socket.

• kwikfix328
• 8 May 2008
• 2

I wanted a dedicated test socket. This one is located just above the main CU and is connected to...