Yes, I did find it in the OSG eventually, tucked away in a note on diversity. A question on what breaker to use for discharge lighting was in a past C&G exam and our course covers a lot of lighting but not what factor to use. I tried looking up 'discharge' in the 18th and reading the outdoor lighting section but couldn't find it.
1.8 factor for discharge lighting. Is it in the Regs Book?
- Thread starter richardindorset
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exam question.
Does this not cover it?
Yes, I understand that power factor is a factor to take into account, but the exam question clearly expects the student to know that discharge lighting needs a 1.8 factor for breaker current selection, without stating a value for power factor.
There doesn't seem to be an obvious regulation in BS7617 for this and it's not taught in the 8202 course, so I just wondered where this factor came from.
It's clearly a bit of 'rule of thumb' sparky folklore that everyone just knows, but it sucks as an exam question! Mind you, C&G are good at those type of questions...
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There's one or two bits in the OSG that don't appear in the regs. They are sometimes "legacy" things that have appeared in older regs but don't any longer.
But many don't like the OSG because it isn't the regs and say they only ever refer to the regs.
But many don't like the OSG because it isn't the regs and say they only ever refer to the regs.
I believe it moved to Guidance Notes/Design Guide. It doesn't actually appear in BS 7671 anymore. That's not to suggest that it shouldn't be applied.
Items mentioned in OSG have the relavent regulation marked next to them. If there’s no reg marked then (as you say) it’s a legacy thing.
I remember that OSG used to say that the should be an isolator switch within 2m of a cooker. But there is no reg for that any more.
What is the actual exam question?
Could the answer be the formula rather than a numerical value?
I.e. the answer is e=mc² rather than the number.
Why would the power factor be in the regulations?
Surely that would be like designing a shower circuit and expecting the power of your shower to be in the regulations.
Could the answer be the formula rather than a numerical value?
I.e. the answer is e=mc² rather than the number.
Why would the power factor be in the regulations?
Surely that would be like designing a shower circuit and expecting the power of your shower to be in the regulations.
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