Safe? Mains to a CFL fitting and bulb

[Gnomer]

Dear electric diynot gurus,

I've looked on the wiki and the how to part. I couldn't find the information I needed.
Is it safe to connect a CFL bulb bayonet fitting straight to the mains?

I have also seen in the diagrams the earth wire is connected. When I look in the bulb fitting there is no hole for the earth!

I really don't want to:
a) burn the house down.
b) electrocute myself.

Thank you for any help.

 

[gram1980]

Hi it sounds like you have a class 2 light fitting which doesnt require an earth connection. There should be a symbol of a square within a square somewhere on the fitting to indicate this.
You should terminate the earths together in a connector block but not connect them to the fitting, then wire switch line and neutral to the lampholder as shown in the diagrams
Hope this helps
Graeme

 

[Gnomer]

Thanks.

I will wrap insulation tape around the end of the earth.

I'm still a little uneasy about the idea of connecting a CFL to the mains (240v). High risk of electrocution right?

I have power adaptors ranging from a PSU 3v-5v-12v and a separate little converter which I think does a max pull of 3A.

 

[ericmark]

If one looks at a CFC like this

Untitled

• ericmark
• 23 Jun 2011
• 2

we see a little switch mode power supply which isolates the coiled florescent tube from the mains. It also corrects any slight voltage variations.

However there are no Class II marking even though we know it is a Class II device. This one a GE 7W 220-240v 50/60Hz 67mA FLE7WCDL/827 Made in China and I think the last bit says all.

I also don't understand when it clearly has a full wave rectifier and would be happy I am sure with DC it's marked as 50/60Hz.

But there is no need for an earth and they are safe. Even though not marked as Class II.

 

[ban-all-sheds]

Thanks.

I will wrap insulation tape around the end of the earth.

No - use a piece of choc-block.

I'm still a little uneasy about the idea of connecting a CFL to the mains (240v). High risk of electrocution right?

Only if you jam your fingers in the socket when fitting the lamp....

Have you never changed a bulb before?

I have power adaptors ranging from a PSU 3v-5v-12v and a separate little converter which I think does a max pull of 3A.

And err......??

 

[EFLImpudence]

I'm still a little uneasy about the idea of connecting a CFL to the mains (240v).

What, exactly, are you getting at? That's how they work.

 

[bernardgreen]

I also don't understand when it clearly has a full wave rectifier and would be happy I am sure with DC it's marked as 50/60Hz.

Many use a capacitor as the current limiting device before the bridge rectifier. Effectively it, together with a larger capacitor on the DC side of the bridge, forms a voltage divider.

 

[ericmark]

I also don't understand when it clearly has a full wave rectifier and would be happy I am sure with DC it's marked as 50/60Hz.

Many use a capacitor as the current limiting device before the bridge rectifier. Effectively it, together with a larger capacitor on the DC side of the bridge, forms a voltage divider.

Not the case with one I broke open 4 x IN4001 diodes and these feed a 1.8uf capacitor rated 400v but I would guess GE has many manufacturers making lamps for them and some may have a capacitor used as you say so would want all with that part number to have same spec shown on them.

 

[Gnomer]

Thanks everyone.

I think I've got more of an idea what's going on.

I have changed a bulb before but I haven't ever made my own lamp, straight from a wall socket. It just feels to me a bit awkward, I guess.

 

[ban-all-sheds]

Thanks everyone.

I think I've got more of an idea what's going on.

I think I've got less of a one...

I haven't ever made my own lamp, straight from a wall socket.

What, exactly, are you trying to do?

 

[davelx]

Not the case with one I broke open 4 x IN4001 diodes and these feed a 1.8uf capacitor rated 400v but I would guess GE has many manufacturers making lamps for them and some may have a capacitor used as you say so would want all with that part number to have same spec shown on them.

Hmm - 1N4001's are rated 50V PIV - if you put a bridge made of those directly on the mains they will likely pop. They should be at least 1N4004's I'd have thought.

 

[JohnW2]

Not the case with one I broke open 4 x IN4001 diodes and these feed a 1.8uf capacitor rated 400v

Hmm - 1N4001's are rated 50V PIV - if you put a bridge made of those directly on the mains they will likely pop. They should be at least 1N4004's I'd have thought.

That was my first reaction, too (and it remains posible that they were decribed as IN4001 in error) - but then I realised that it could be far more complicated than it sounds. I think it depends upon what is on the load side of the bridge; with a 1.8uF capacacitor (reactance about 1768Ω at 50Hz) feeding the bridge, and with one pair of diodes always conducting (hence current always flowing through that capacitor), depending on the load it could be that the reverse voltage across the diodes never exceeds 50V.

Just a thought! However, 'common things are common', so it was probably just a typo!

Kind Regards, John.

 

[ban-all-sheds]

One thing you can guarantee is that whatever is inside one of those CFLs will be the cheapest nastiest set of components they can get away with...

 

[JohnW2]

One thing you can guarantee is that whatever is inside one of those CFLs will be the cheapest nastiest set of components they can get away with...

That's exactly what I was thinking. If the situatio is that they can just about get away with IN4001s, that might save them a fraction of a penny per unit,so they'd do it!

Kind Regards, John.

 

[sparkwright]

Thanks everyone.

I think I've got more of an idea what's going on.

I have changed a bulb before but I haven't ever made my own lamp, straight from a wall socket. It just feels to me a bit awkward, I guess.

This, and your first message, are not particularly clear about what you are trying to do.

If you feed a light from a wall socket you need to check first that the socket is capable of supplying another feed hardwired into it. Be aware of adding to spurs and sockets and junction boxes already supplying a spur on ring circuits.

From the socket wiring usually 2.5 mm2 cable will supply a fused connection unit, typically with a 3 or 5 amp fuse. This can be switched or unswitched. From here 1.0 or 1.5 mm2 cable to the light, and light switch as required. All bare earth wires sleeved with green and yellow sleeving, and all connected together.

Or are you intending on just plugging the light into the wall socket??

Apologies if I have misunderstood your posts - they don't make a lot of sense.