Grey 2 Core Vff Cable (one With Black Line: Which Is Neutral?

[gdhm]

Hi,

Quick one for the experts as I was unable to find answer on web

I have just bought outdoor plastic and glass wall lanterns on opening he box I noted they do not have a ground wire and they use 2 core VFF size 2 x 05 sq mm 300V grey insulated (both) cable. One of the two has a solid black line running down its length.

Please can someone tell me if this black solid line indicates the Neutral or Live (I am assuming Neutral at present).

The cabling in my house to the lanterns is Ground, Neutral and live wires. I am unsure when lighting only uses 2 core (Live and Neutral) how important it is to get the wires the correct way around but am assuming it is important hence my question.

Thanks Dave

Edited December 15, 2009 by gdhm

[longball53098]

If you have a VOM (Volt-Ohm Meter) then a simple continuity test of the light fixture before you connect any cable to it should tell you if the black lead is hot or neutral.

If the fixture uses the typical screw in lamps then the center bottom of the socket is a contact that is normally the hot side for the light bulb. The side of the socket that are the screw threads are normally the neutral side of the light.

So if the meter test lead is connected to the black lead and the other test lead to the inner base of the socket you should have continuity and this would tell you the black wire is the hot side and the non black is neutral. To verify this move the test leads to the other non black wire and the sides of the screw socket and again you should have continuity.

If the entire housing of the light is made from a metal then attaching you're earth wire to the metal case will work for earthing the light fixture. If its plastic then you really have nothing to ground as if something happens to the hot wire where it contacts the case of the light the plastic will not conduct to make the fixture "hot" so to speak. I think better to have a ground fault circuit here as protection.

[gdhm]

If you have a VOM (Volt-Ohm Meter) then a simple continuity test of the light fixture before you connect any cable to it should tell you if the black lead is hot or neutral.

If the fixture uses the typical screw in lamps then the center bottom of the socket is a contact that is normally the hot side for the light bulb. The side of the socket that are the screw threads are normally the neutral side of the light.

So if the meter test lead is connected to the black lead and the other test lead to the inner base of the socket you should have continuity and this would tell you the black wire is the hot side and the non black is neutral. To verify this move the test leads to the other non black wire and the sides of the screw socket and again you should have continuity.

If the entire housing of the light is made from a metal then attaching you're earth wire to the metal case will work for earthing the light fixture. If its plastic then you really have nothing to ground as if something happens to the hot wire where it contacts the case of the light the plastic will not conduct to make the fixture "hot" so to speak. I think better to have a ground fault circuit here as protection.

Thanks Longball. Unfortunately I was well advanced in the replacement insulation when I ran into the grey wire insulation of the all plastic casing lanterns and felt sure (silly me) it would be easy with as Google search to find out conventions for a solid black line down on all grey 2 core wiring wire covering. BUT NO! Found plenty of pictures no full descriptions , and other flexes in my house with dotted blue line on all white wire casings.

Now I have already (finished installing) as it was getting dark and I do not wish to risk rain over night on half exposed wiring. I have assumed the black line down one of the two grey wires insulation casings is NEUTRAL.

Just my luck if I have assumed wrong as your very valid signature saying will come into play and I will have to dissemble and correct tomorrow

Luckily I will store you advice for future situations as that is very helpful.

I have ground wiring to a copper rod for nearly all the house and garden but sometimes the fixture as today does nto have an Ground wire or connection. This time I assume because the casing is is all plastic and glass so well insulated.

Is there an easy way to tell which of two main wires is Neutral and which is Live using a multimeter. I think the electrician who did the wiring for my house was pretty good and careful BUT I prefer to check when I have cause to reconnect or replace an items myself.

Regards, Dave

[powderpuff]

Yeah. Get one of those tester screwdrivers. Live will make it light up - N will not.

Side note. When I buy light fixtures I usually upgrade the wiring myself. I'll buy a meter each of red & black 1.0 mm2 solid core copper wire & get rid of that junk they come with. 05 mm2 is ok 1.0 is much better. Then I use red for live.

Edited December 15, 2009 by powderpuff

[gdhm]

Yeah. Get one of those tester screwdrivers. Live will make it light up - N will not.

Side note. When I buy light fixtures I usually upgrade the wiring myself. I'll buy a meter each of red & black 1.0 mm2 solid core copper wire & get rid of that junk they come with. 05 mm2 is ok 1.0 is much better. Then I use red for live.

Thanks will do.

Anybody yet know what the black (or dotted lines on some 2 core are meant to imply (Neutral or Live wire)?

Or whether on a light it is important which way round I connect when only live and neutral wires.

Do ELP bulbs care?

Dave

[longball53098]

Sorry I don't know the acronym of "ELP" . Is that a long life lamp?

Electrically it makes no difference which part of the light fixture is wired to hot and neutral. The end result is the lights works.

IMHO the shell or screw threads of the socket should be neutral for a measure of safety when unscrewing the light bulb should you happen to touch the threads when screwing in or out this part will be neutral should you be the path to earth. You of course should always have the power off when changing a lamp but many many folks don't do this and leave the switch on when replacing the light.

[gdhm]

Sorry I don't know the acronym of "ELP" . Is that a long life lamp?

Electrically it makes no difference which part of the light fixture is wired to hot and neutral. The end result is the lights works.

IMHO the shell or screw threads of the socket should be neutral for a measure of safety when unscrewing the light bulb should you happen to touch the threads when screwing in or out this part will be neutral should you be the path to earth. You of course should always have the power off when changing a lamp but many many folks don't do this and leave the switch on when replacing the light.

Sorry longball MY error.

I meant ES

(just checked my bulbs - now need to check brain and memory )

Thanks for the info

I always have power switch off (unless a mistake) as I worry if it exploded my eyes and face usually would be near. Not sure if ES are safer than incandescent but my nature instinct is to play safe always (why risk when so easy and quick to avoid all risk).

Dave

Edited December 16, 2009 by gdhm

[powderpuff]

I think the dashed line means live but who knows - that is just a WAG. As stated above the center prong is live & the threaded part (socket) is Neutral. Confirm this for yourself. Don't trust some Chinese making 50 cents per hour to do it right.

[powderpuff]

WTH is ES? from one unknown acronym to another.

[stgrhe]

WTH is ES? from one unknown acronym to another.

Could it possibly mean energy saving?

[gdhm]

WTH is ES? from one unknown acronym to another.

Could it possibly mean energy saving?

Sorry again.

Yes it is "Energy Saving". They are the almost as small as old incandescent bulb sizes lighting but fluorescent.

Most buy ES these days. Some have names like Tornado, Twister mini Twister, Genie some are 2 or 3 bars (not twists) Watts like 9W 11W 18W 20W 25W etc. and come in cool, daylight or warm light tones.

I suspect in the fairly soon future we will all move on to LED (Light Emitting Diode) lighting when prices drop as they can be dimmed (big plus for some) and I am told use even less power for various levels of brightness. Just look at the brightness of LED torches.

Dave

Edited December 16, 2009 by gdhm

[powderpuff]

In my home country they are known as "Compact Flourescent". Nuff said. I am here to help the guy.

[gdhm]

In my home country they are known as "Compact Flourescent". Nuff said. I am here to help the guy.

That's very interesting powderpuff .

Except for my error with ELP I did expect ES to be universal but now I know differently.

In future I will bear this in mind in future and either be more detailed or state what country's terminology I am using. Probably important bearing in mind TV members and reader come from all over the World.

Regards

Dave

[Altos]

In my home country they are known as "Compact Flourescent". Nuff said. I am here to help the guy.

That's very interesting powderpuff .

Except for my error with ELP I did expect ES to be universal but now I know differently.

In future I will bear this in mind in future and either be more detailed or state what country's terminology I am using. Probably important bearing in mind TV members and reader come from all over the World.

Regards

Dave

Guys - ES SHOULD refer to Edison Screw which is the type of base the bulb has. The other type is Baynet or BC. This has nothing to do with the bulb type, except some bulb types such as sodium commercial, are AFAIK only available in ES, actually Giant ES. (GES)

There are energy saving bulbs as cool fluoro (causes light by the passage of electrons thru the gas) as someone said above and there are halogen bulbs which are filament bulbs but about 30% more efficient in light output as halogen allows greater heating of the filament and therefor recommended as energy efficient.

The ones I have seen here in Australia are actually a small halogen bulb in a more conventional outer glass case and so look identical to the old incandescent.

Apart from that, for our guy above wiring his lamp. In addition to the other good tips given it is also wise to check that the "hot" wire is the one that is in fact going through the switch and then to the centre contact in the bulb holder. If the hot one is bypassing the switch you could have a nasty experience despite it "appears" to be switched off.

Anyone really interested in light bulb technology could read

http://en.wikipedia.org/wiki/Incandescent_light_bulb

it is actually quite interesting.

Retired Engineer.