PIR 50 watt fuse

[pidgeon1]

What fuse should use for a 50 watt LED PIR flood light ?

 

[RandomGrinch]

3 Amp

 

[pidgeon1]

3 Amp

Thanks, that was a quick reply.

 

[Taylortwocities]

Thanks, that was a quick reply.

It was a simple question!

 

[pidgeon1]

It was a simple question!

When you know the answer everything simple

 

[ericmark]

Watts = Volts x Amps x Power factor correction, so Amps = Watts / (Volts x Power factor) with LED the power factor can be as low as 0.5 so 0.43 amps, but smallest fuse is 1 amp, and we tend to fuse to protect cable so the preferred sizes are 3 amp and 13 amp, so answer is 3 amp.

With tungsten the limit for a flood light was 150 watt without planning permission, I don't know if the law has been rewritten using lumen instead of watts? But with LED one would normally consider 30 watt maximum to comply with the sprite of the law.

 

[Rodders53]

1 Amp will do, too.

With tungsten the limit for a flood light was 150 watt without planning permission, I don't know if the law has been rewritten using lumen instead of watts? But with LED one would normally consider 30 watt maximum to comply with the sprite of the law.

Dunno where you get that idea from
https://www.planningportal.co.uk/permission/common-projects/lighting/lighting-planning-permission clearly states otherwise for domestic at least.

50 Watt LED is imho going to be far too bright as a replacement for the OP's 300 Watt halogen floodlight (which would likely have had a 3 Amp fuse in the supply). https://www.diynot.com/diy/threads/pir-flood-light-what-one-is-best.604256/

Building Regulations do apply though

Building Regulations - Lighting - Planning Portal

Details of the planning permission and building regulation regimes for Lighting in England

www.planningportal.co.uk

and have that 150 Watt number mentioned (with no differentiation between LED or tungsten halogen on that page - the regs may be more specific, or not?).
A >40 lumen per watt efficacy is required (50 Watt x 40 = 2000 lumens) so the 50W led floodlight will easily surpass that requirement.

 

[JohnW2]

1 Amp will do, too.

Indeed. I must be one of the few people around who uses a lot of 1A fuses - not really necessary, but 'why not?' if they are adequate?

Dunno where you get that idea from
https://www.planningportal.co.uk/permission/common-projects/lighting/lighting-planning-permission clearly states otherwise for domestic at least.

Quite so, but eric is always making that assertion.

50 Watt LED is imho going to be far too bright as a replacement for the OP's 300 Watt halogen floodlight (which would likely have had a 3 Amp fuse in the supply).

Agreed.

Building Regulations do apply though .... and have that 150 Watt number mentioned (with no differentiation between LED or tungsten halogen on that page - the regs may be more specific, or not?).

Approved Document L (which, unlike the Building Regs themselves, is not 'law') contains only guidance/recommendations, not any 'requirements'.

A >40 lumen per watt efficacy is required (50 Watt x 40 = 2000 lumens) so the 50W led floodlight will easily surpass that requirement.

True, but you are again talking about recommendations, not 'requirements'.

Kind Regards, John