Does 1 watt make a difference?

[type-r]

I bought a set of tail light bulbs P21/5w however the manufacturer handbook recommends P21/4w. Does 1w make a difference in terms of safety / electrical fire etc?

[Krikkit]

1W wouldn't make a difference, but (confusingly) that's not what the P21/xW is about, that refers to the fitment shape. Both of them are 21 Watt bulbs, the only difference is how the retaining lugs are spaced.
4W

5W

Edited by Krikkit on Tuesday 5th November 07:41

[type-r]

Ok cheers for the info, very useful and interesting. As the fitment lug is offset 30 degrees from the plane in 4w, 5w won't fit. Cheers for that.

[SV8Predator]

Bright tail light bulbs?

[cobra kid]

380/382

[andym1603]

380 - stop/tail. Twin filament 21/5 watt
382 - tail. Single filament 21 watt

[Mr2Mike]

andym1603 said:

380 - stop/tail. Twin filament 21/5 watt
382 - tail. Single filament 21 watt

A 382 will be a stop, indicator or rear fog lamp. Rear tail lights tend to use 5 watt lamps.

[type-r]

Just to be clear, the reason why I went for a 380 instead of the recommended 382 in the shop, was that 382 had a single contact whereas the bulb I removed from the car had a twin contact. I went for the twin contact 380 but didn't realise the lugs where offset as they are shown in the pic above!