I have a quite large old hanging lamp, which might have hung outside a pub or restaurant, but the old bayonet fixture has no label or sticker indicating the maximum bulb wattage.

How do I determine the maximum wattage to make sure I don't overheat the cable or lamp socket?

hjp, June 2008

Thanks, that makes sense. This is a quite large fixture that probably hung outside a pub or restaurant, so I'll try 100W and just keep an eye on it for awhile before committing.

hjp, June 2008

You can't really - the cable and bulb holder will be able to take the current involved more than likely - its the surrounding plastic or metalwork that may overheat. Aim safe - go for a 60w bulb if possible and its bright enough for you. If its a large item with plenty of space between the bulb and the glass or frame a larger bulb of 100w, maybe 150w should be ok. Why not use an energy saving bulb? If it will physically fit you'll have no problems regarding the wattage.

John, June 2008