Maximum current through RCD.

[Plug]

Thanks for the reminder, I'd forgotten about the separate RCDs.

Probably will go for something like:
[code:1]
-- RCD --- 6A MCB --- Lights
¦
Supply --- Main Isolator --- 16A MCB ---
¦
-- IP55 13A socket with RCD
[/code:1]

Should the 6A MCB be a type C one, the lighting is 6x 150W tungsten floodlights?

(I have to use the 6A MCB, as the lights have 1.5mm^2 cable.

 

[plugwash]

yes if you have that much halogen on a 6A breaker you will wan't it to be a C type.

but you are still putting all the lighting on one RCD.

 

[RF Lighting]

Should be fine on a 6A MCB though your 1.5mm² would be ok on a 10A MCB. A type 'C' MCB would be better to prevent the breaker tripping in the event of a lamp failing but a type 'C' must only be used if your EFLI value is low enough (The highest reading (usually the last point on the circuit)) which might be a problem on a supply with an earth spike. (Max values for type 'C' breakers to BSEN60898 6A mcb = 3.20ohms, 10A MCB = 1.92ohms) these values must not be exceeded. The use of a 6A type 'B' MCB would allow a Zs of upto 6.40ohms

 

[Spark123]

The enclosure in your earlier post should take RCBOs. If the generator earthing is from an earth spike then it will be a TT arrangement...

I thought it will be TN-S if the neutral is connected to earth, if the neutral is not connected to earth then it either needs the neutral to be linked to earth or needs to meet the requirements for electrical separation (i.e. DP MCBs, not earthed, eq bonding etc). Just because a generator has an earth point on the chassis it does not mean there is a neutral to earth link in the generator, this needs to be clarified with the manufacturer of the generator and how to go about the link. It also becomes more complicated to check a generator electrode as a simple efli check can't be done, a specialist electrode tester is required.

 

[Plug]

If the generator earthing is from an earth spike then it will be a TT arrangement. If you are connecting the marquee frame to earth then it needs to be connected to the MET.

Does connecting to the MET mean running a separate earth line from the Marquee frame straight back to the spike next to the generator (30m away)? I've heard that this cable should be as large as possible, am I looking at a 10mm^2 line?

Earth rods should be tested with a proper earth rod tester.

Am I right in thinking that this is something that not all sparks will have?

But you are still putting all the lighting on one RCD.

It's getting late and I'm not thinking properly! I need to chew this over.

Should be fine on a 6A MCB though your 1.5mm² would be ok on a 10A MCB. A type 'C' MCB would be better to prevent the breaker tripping in the event of a lamp failing but a type 'C' must only be used if your EFLI value is low enough (The highest reading (usually the last point on the circuit)) which might be a problem on a supply with an earth spike. (Max values for type 'C' breakers to BSEN60898 6A mcb = 3.20ohms, 10A MCB = 1.92ohms) these values must not be exceeded. The use of a 6A type 'B' MCB would allow a Zs of upto 6.40ohms.

I assume there's no way of knowing exactly what this will be until it's installed, I really will need to get someone in. The floods will probably be attached to the frame of the marquee too, in order to complicate this further.

This system is being specified with the intention of setting it up in the same place for this event on an annual basis. I'm assuming that it will only need a pro to come and look at it one this one occasion. Is this a good assumption or not?

 

[plugwash]

Earth rods should be tested with a proper earth rod tester.

Am I right in thinking that this is something that not all sparks will have?

fraid so, if mains is availible than an earth fault loop tester can be used to test a rod but testing a rod to be used for a generator setup without mains availible requires two extra temporary rods and a special meter.