Voltage Detector

[skind56]

Hi

I'm having a new front door installed soon and will require to re-fit the doorbell and burglar alarm door contacts.
I can isolate the current by use of one circuit breaker switch that does for both the bell and burglar alarm but I wish to ensure no current by use of a voltage detector - just to be sure.

Which voltage detector would be recommended for such a task?

Thanks in advance for any help.

Regards
Steve

 

[pc1966]

2 prong volt testers only use batteries for continuity tests. they will indicate voltage without batteries or if the batteries are dead.

True, but sometimes the voltage-range bit does not work and it looks as if it is 12V or similar as only one LED comes on.

I know some folk really like having continuity checking in a voltage tester but I always jump when checking for an energized N and it squeals only to realise a second later it is a different squeal and it telling me N & E are common back at the supply and the TPN switrch is not switching N as well, etc.

 

[dodger421]

I got one of these proving units which it relatively inexpense:
https://www.cef.co.uk/catalogue/products/4457482-proving-unit
Needs only a light probe pressure to work, also has a button for checking non-contact detectors.

As an aside, the non-contact detectors have their use for seeing if something is live (e.g. tracing which cable is on without having to gain access to junction boxes, etc) but never for proving dead. Basically you only use them for some aspects of convenience but you can never rely on them to detect power or the lack of it. Generally I would advise not to get one as the temptation to use it inappropriately may be too high,

I bought the Stroma PU a year or two ago because it was a good price and seemed pretty rugged. It’s served me well but I’m tempted by the socket&see one with the non-contact prover just for those times when they can be useful. All 3 look very similar, I’d suspect they were from the same factory even.

https://testermans.co.uk/product/new-socket-see-sp400-ac-50-690v-proving-unit/

I know some folk really like having continuity checking in a voltage tester but I always jump when checking for an energized N and it squeals only to realise a second later it is a different squeal and it telling me N & E are common back at the supply and the TPN switrch is not switching N as well, etc.

I can relate to the jumping, you never quite get used to the squealing. I find I can do the majority of my fault finding with my T110, though that is pretty much all industrial work with the odd bit of facilities/building maintenance. There are always occasions you need other test equipment, it just comes back to using the right tools for the job.

 

[Lister1987]

You also recommended this one to me, thanks. Screwfix are usually all right, and the price is really good.

But: any idea if this model meets the GS38 requirements? It doesn't say one way or another on the Screwfix description. Do you know if it says on the packaging?

Are we not better shelling out £50 on a model that explicitly says it meets GS38? Or are you trying to be realistic about what DIYers will spend, that they're better buying this 2 pole tester, if the alternative is them relying on a non-contact tester?

A 2 pole tester that is designed to BS EN 61243-3 is deemed to meet GS38 requirements, you should be able to find literature for the equipment stating this, if the tester does not comply with BS EN 61243-3 then it is unlikely to meet GS38.

See; https://martindale-electric.co.uk/2...tion-what-you-need-to-know-to-stay-compliant/

 

[Ziggie]

The regs say a proving unit or a near by other circuit. I test mine in a live socket near where I am working.

The regs say GS38 compliant and that’s what I use but luckily you can remove the tip covers when the tips don’t reach the terminals e.g. Wago connectors and possibly some sockets.

while I almost always use my 2 pole now as it also shows the voltage on a display and this serves well for problem solving.

 

[pc1966]

While not exactly the thread subject, strongly related is the "safe isolation" process. Here is a link to the Best Practice Guide #2 on the matter:
https://www.----------------------------/media/1201/best-practice-guide-2-issue-3.pdf

 

[inquisitive]

Thanks all for your comments. A bit to digest!

 

[Telecoms_man]

If just removing the door contacts, the wires going to them will be a voltage of 12V and very low current, so no need to isolate the alarm panel and remove the battery. I doubt whether a GS38 voltage indicator would even register.

I assume the doorbell is mains voltage powered? Even then the door push button itself will be of a very low voltage, so again no need for isolation.

Or have I missed something as to why door contacts and a doorbell push need to be isolated?

 

[pc1966]

Certainly a doorbell ought to be safe low voltage and no real need for the above.

But the question started on voltage testers and if you are testing for the possibility, even if very small, that someone or something has left a circuit at a dangerous voltage you should always start from the assumption it is dangerous, until proven otherwise.

So you should really use test equipment that is safe for what might be present. Also for any other job in the future where you know it would normally be 230V, etc.