13a fcu/ rcd feeding conservaory + lighting

[darren bergin]

13a fcu / rcd feeding conservatry off ring
feeds 2 x dbl sockets and two lighting points noticed there is no seperate fcu for lighting but fed off same 13arcd
is there a requirement for seperate fcu or is this ok

also on test results what is given for zs on the circuit is it 1667 because its rcd protected?? or do you have to give actual result via test meter?

thanks

 

[mikhailfaradayski]

prbbly nt v gud prctise 2 av lghtsnsckts fed 2getha lik tht bu if the cble is prtectid thn nt rquirmnt to av 3afcu.
y nt mesur zs , its ezee ?

 

[darren bergin]

is your keyboard shagged .m8?

 

[darren bergin]

just askin whats the norm?,, some sparks put the 1667 figure down????

 

[Taylortwocities]

Results should be by measurement or by calculation.

You are going to need to know the Ze at origin. You've got some earthing to sort out if its anywhere near 1667ohms.

You may not have understood Mr F*ski but (as he tried to say) measuring Zs is easy so do that and you write the reult on the cert. What's the problem with doing that?

 

[mikhailfaradayski]

sorry about yesterday, it must have been something i ate, gave me dodgy vowels.

When you are filling in the value of Zs, does it ask for the actual value or a maximum permissable value?
If you just put 1667 since you know its the max, don't you think it might suggest to others in the know that you haven't actually checked it? Looks a bit rubbish and would concern me that you obtained that value- what about volt drop on that circuit?

 

[1john]

TT supply??

 

[darren bergin]

excuse my ignorance

but suppose on tn system the measured zs is slightly above permissable using bs en 60898 32a figures table 41.3

would i still put the measured figure on the certificate

even though its above max allowed, but overall the circuit is protected by rcd, so ok.

 

[mikhailfaradayski]

Who is responsible for the design of the circuit with the high Zs?
Why don't you ask that person about their ability to design a circuit?
What do you think to the three questions i asked in my last post?

 

[Adam_151]

If the value is within spec for the OCD, then put the max zs for that for 'maximum zs' , if its a bit out, then its a little rough but if its on a 30ma RCD then you can get away with putting 1666 for max zs (though I'm sure all the times I've had to do this, its only too high because my non tripping loop setting is a bit pants!)

measured zs should always be measured value of zs (or in some cases, calculated from Ze and R1+R2)

 

[mikhailfaradayski]

Hi Adam,
sorry for disagreeing, but the sheet in the EIC where you enter this data is the 'schedule of test results' that would imply that the number entered is a result of a test carried out, not a 'maximum allowable' figure.

I would be concerned about the integrity of either the design or the installation if i saw 1667 entered. Assuming max Ze on a TNS supply and use of 1.5 T+E, that would indicate a circuit length of over 55 kilometres or a bad connection.