Ask an Electrician anything...

[markiii]

USB Cig lighter charger plug

[spikeyhead]

dundarach said:

Where can I find a simple module to convert 12v DC to 5v DC that's small and simple to use which doesn't create much heat?

Ideally two wires in and out and 1cm2

https://uk.farnell.com/w/c/power-line-protection/power-supplies/dc-dc-converters?st=dc-dc%20convertor&gs=true

[Baldchap]

Going to be done by a sparky but I want to check if it's doable.

We have a new garage going up. We have our main three phase breakers in a different garage and one of these is then linked to a three phase distribution board in part of the house near the new garage.

This distribution board in the house has spaces for new three phase breakers, is it permissible to chuck a big one in and then feed this to the new garage being built, and fit a smaller three phase distribution board in there to run the door motor (big boy), lighting and sockets etc and a possible EV charger or two in the future, or does this need to come from the main power in for the whole property?

Thanks.

[silentbrown]

dundarach said:

Where can I find a simple module to convert 12v DC to 5v DC that's small and simple to use which doesn't create much heat?

Ideally two wires in and out and 1cm2

Simple answer is two resistors, as you haven't specified the required current...

What's the application?

[Bazsm]

dhutch said:

I would also ask, why?

The consumer box is high up on the garage wall, we had an RCD trip last year in the middle of the night during a storm and it's difficult to get to in the pitch black when you're panicking. By moving it into the house it seems like a good way to minimise problems in the future as we get older!

[dhutch]

dundarach said:

Where can I find a simple module to convert 12v DC to 5v DC that's small and simple to use which doesn't create much heat?

Ideally two wires in and out and 1cm2

Ebay.....

[Steve Campbell]

Is there a simple way to find out why no power is being fed to a light ?

Here's the problem > When we moved in 17 years ago, I had a large drinks cabinet for the dining room. Dining room had 3 uplighters. I removed the uplighter and made safe the wires on one of them where I wanted to put the cabinet against the wall. No idea if it was working at the time as this was on the day of moving in.

17 years later, the cabinet has gone and new uplighters now fitted....but the one that was blanked off doesn't work !

I have an electrician coming around next week anyway but was just wondering. Electrician also going to fix my idiot mistake of replacing other lights and not checking what wires connected to what before disconnecting the light.....so I have 4 wires coming in consisting of 4 reds, 3 blacks, one blue and 2 earths !.......and have no idea which one is the switch etc etc ! Just so happens the first one I took apart is the primary link to all the others (4 other lights and 2 other rooms !). Oh well........

[Actual]

dundarach said:

Where can I find a simple module to convert 12v DC to 5v DC that's small and simple to use which doesn't create much heat?

Ideally two wires in and out and 1cm2

I used this

https://www.amazon.co.uk/dp/B00J1E1IG6/ref=pe_3857...

[Actual]

Steve Campbell said:

Is there a simple way to find out why no power is being fed to a light ?

Here's the problem > When we moved in 17 years ago, I had a large drinks cabinet for the dining room. Dining room had 3 uplighters. I removed the uplighter and made safe the wires on one of them where I wanted to put the cabinet against the wall. No idea if it was working at the time as this was on the day of moving in.

17 years later, the cabinet has gone and new uplighters now fitted....but the one that was blanked off doesn't work !

I have an electrician coming around next week anyway but was just wondering. Electrician also going to fix my idiot mistake of replacing other lights and not checking what wires connected to what before disconnecting the light.....so I have 4 wires coming in consisting of 4 reds, 3 blacks, one blue and 2 earths !.......and have no idea which one is the switch etc etc ! Just so happens the first one I took apart is the primary link to all the others (4 other lights and 2 other rooms !). Oh well........

FLUKE AC NON-CONTACT VOLTAGE DETECTOR PEN 1000V AC
https://www.screwfix.com/p/fluke-ac-non-contact-vo...

Unlike other pen type detectors this one is more safe to use and will glow red when you position it next a live wire.

Just so you know it is working it is advisable to make sure it is turned on and check a known live wire before and after checking the wire being tested.

Edited by Actual on Thursday 4th April 11:34

[silentbrown]

Actual said:

Unlike other pen type detectors this one is more safe to use and will glow red when you position it next a live wire.

I'm interested as to why...?
I've got one of these at a third of the price, and it hasn't killed me yet.
https://www.screwfix.com/p/lap-ac-non-contact-volt...

[Actual]

silentbrown said:

Actual said:

Unlike other pen type detectors this one is more safe to use and will glow red when you position it next a live wire.

I'm interested as to why...?
I've got one of these at a third of the price, and it hasn't killed me yet.
https://www.screwfix.com/p/lap-ac-non-contact-volt...

The model that you have identified is also supplied by Screwfix is also a non contact tester and presumably work the same way as the Fluke example.

Other screwdriver testers require direct contact with the live wire and the operator has to touch the cap of the screwdriver to make a circuit.

I would not use the following example also from Screfix and costing £1.49 for 2.
https://www.screwfix.com/p/slotted-vde-voltage-tes...
How do you test a live wire screwdriver?
Insight - How electrical Line Tester screwdriver works
In order to test the live wire, the user's body must be in contact with the metal cap on the top of the screwdriver when the tester is put in contact with the wire. This completes a genuine electrical circuit and the bulb will light up once the tester senses voltage.

Using this type of tester there could be a greater possibility of electric shock or electrocution.

Edited by Actual on Thursday 4th April 12:32

[dhutch]

I wouldn't used a £1.50 unbranded neon screwdriver but I have a £6 unit I have no fear of using around the house testing normal domestic mains wiring for live. Typically this is done after I have isolated, but I have also used it for fault finding. Obviously doesn't work if the cable is buried in the wall!

https://www.toolstation.com/wera-mains-tester-scre...

[silentbrown]

Actual said:

The model that you have identified is also supplied by Screwfix is also a non contact tester and presumably work the same way as the Fluke example.

Other screwdriver testers require direct contact with the live wire and the operator has to touch the cap of the screwdriver to make a circuit.

I would not use the following example also from Screfix and costing £1.49 for 2.
https://www.screwfix.com/p/slotted-vde-voltage-tes...

Sure. I was just surprised you said "other pen type detectors". Those obvs. aren't pen type ones.

[Actual]

silentbrown said:

Actual said:

The model that you have identified is also supplied by Screwfix is also a non contact tester and presumably work the same way as the Fluke example.

Other screwdriver testers require direct contact with the live wire and the operator has to touch the cap of the screwdriver to make a circuit.

I would not use the following example also from Screfix and costing £1.49 for 2.
https://www.screwfix.com/p/slotted-vde-voltage-tes...

Sure. I was just surprised you said "other pen type detectors". Those obvs. aren't pen type ones.

Sorry...

The pen is mightier than the screwdriver

[Ganglandboss]

silentbrown said:

Actual said:

Unlike other pen type detectors this one is more safe to use and will glow red when you position it next a live wire.

I'm interested as to why...?
I've got one of these at a third of the price, and it hasn't killed me yet.
https://www.screwfix.com/p/lap-ac-non-contact-volt...

The only safe means of proving an electrical supply is dead is a set of GS38 test lamps, used by somebody who knows what they are doing. Just because a stty non-contact voltage pen has not killed you yet does not make it safe.

'Actual' is also talking utter bks.

Edited by Ganglandboss on Friday 5th April 01:26

[mickk]

Ganglandboss said:

The only safe means of proving an electrical supply is dead is a set of GS38 test lamps, used by somebody who knows what they are doing. Just because a stty non-contact voltage pen has not killed you yet does not make it safe.

'Actual' is also talking utter bks.

And don't forget you'll need a GS38 proving set to test the tester before and after use.

[Greshamst]

I’ve just moved into a new house.

Whenever the hot water cylinder clicks on, the ceiling light in the room next door switches off, or goes dim. (The light and water cylinder then play a dance of going on and off with eachother)

Is this something I could turn off all the fuses for and investigate myself, or should I just call an electrician to investigate?

Electrics is not something I’ve had to get involved in before, and would like to remain alive where possible.

[Regbuser]

Could be an incorrectly connected, or 'borrowed' neutral.
Best get an electrician in.

[silentbrown]

Ganglandboss said:

Just because a stty non-contact voltage pen has not killed you yet does not make it safe.

They're an excellent and quick first line of defence (which I know is not the same as 'proving dead'). Not sure how else you're going to easily spot faceplate screws that have become live.

[GasEngineer]

Actual said:

Steve Campbell said:

Is there a simple way to find out why no power is being fed to a light ?

Here's the problem > When we moved in 17 years ago, I had a large drinks cabinet for the dining room. Dining room had 3 uplighters. I removed the uplighter and made safe the wires on one of them where I wanted to put the cabinet against the wall. No idea if it was working at the time as this was on the day of moving in.

17 years later, the cabinet has gone and new uplighters now fitted....but the one that was blanked off doesn't work !

I have an electrician coming around next week anyway but was just wondering. Electrician also going to fix my idiot mistake of replacing other lights and not checking what wires connected to what before disconnecting the light.....so I have 4 wires coming in consisting of 4 reds, 3 blacks, one blue and 2 earths !.......and have no idea which one is the switch etc etc ! Just so happens the first one I took apart is the primary link to all the others (4 other lights and 2 other rooms !). Oh well........

FLUKE AC NON-CONTACT VOLTAGE DETECTOR PEN 1000V AC
https://www.screwfix.com/p/fluke-ac-non-contact-vo...

Unlike other pen type detectors this one is more safe to use and will glow red when you position it next a live wire.

Just so you know it is working it is advisable to make sure it is turned on and check a known live wire before and after checking the wire being tested.

Edited by Actual on Thursday 4th April 11:34

From the post it seems that he trying to determine the cause of no power at the light fitting, having presumably already established that its not live.

Edited by GasEngineer on Friday 12th April 13:19