Garden Shed lights

istabraq

I am wiring a garden shed and i am going to spur off of a socket circuit in the house but i want to put flourscent lights in the shed,Im just wondering will the flourscents effect the Rcd has anyone ever come across this or should i be ok.Thanks

davelerave

shouldn't trip.but a socket fault knocking out shed lights could be a nuisance

Ddad

the sparky that installed the sockets and the light in my shed installed a waterprof board so that the shed is independently fused. Off of a socket circuit in the house too. Armoured cable.

davelerave

Ddad wrote: »

the sparky that installed the sockets and the light in my shed installed a waterprof board so that the shed is independently fused. Off of a socket circuit in the house too. Armoured cable.

you've a separate board in the shed, but you're connected to a socket circuit.a 'true' independent supply goes back to fusebox.

2011

the sparky that installed the sockets and the light in my shed installed a waterprof board so that the shed is independently fused. Off of a socket circuit in the house too. Armoured cable.

It is a little strange to supply a sub board from a socket circuit. If the sockets in the house fail, so will all circuits fed from the board in the shed. Generally if a shed is supplied from a socket circuit the lights in the shed are simply fed from a fused spur outlet. Otherwise the shed board is normally fed directly from the main board.

Stoner

istabraq wrote: »

I am wiring a garden shed and i am going to spur off of a socket circuit in the house but i want to put flourscent lights in the shed,Im just wondering will the flourscents effect the Rcd has anyone ever come across this or should i be ok.Thanks

It's not the best way to do things. You should at least fuse down the cable feeding the light to 10 Amp. People offer that table lamps run from sockets, but they forget that they have a fused plug top. Some would suggest using a fitting that has a built in fuse, like a 38 Watt vapor proof fitting. However this correction of the fuse size will not improve the RCD situation highlighted by davelerave. The RCD will still work, it's just that it doing it's job might cause an issue.

istabraq

I am going to fuse down to 5 amp for the lighting circuit with a fused spur but was just wondering about the fluorscents tripping the rcd i know ordinary bulbs won't trip the rcd but i have heard fluorscents shouldn't be on an rcd because of starting current can cause rcd to trip?

2011

They will not trip the RCD.

This type of light (fluorscent) is an inductive load, so they can be harsh on switches. If you are switching a few of them through a switch it should be "de-rated". This means use a switch that is rated to switch a current that is at least 1.8 times the load current.

davelerave

afaik leakage from fluorescent electronic ballast system is 0.2-0.5 ma( but they have smaller inductor due to higher frequency).magnetic ballast lighting has no leakage in-built but may have large spike afaik.circuit protection for bank of these lights (rcbo)could have 'c' type characteristic
for the start inrush and a short time delay on rcd(or internal filter) for any transient. number of electronic would be limited anyhow due to accumulated leakage .some info here.http://www.ferret.com.au/c/ABB-Australia/AP-R-residual-current-device-from-ABB-Australia-n820483

2011

afaik leakage from fluorescent electronic ballast system is 0.2-0.5 ma

The RCD installed in a house should operate at 30mA. Therefore in theory it would take at least 60 of the above fittings to cause the RCD to trip.

Unless it is a very large shed with many fluorscent lights the OP will be fine from that point of view.

Using C type RCBOs or MCBs has other consequences; a lower earth fault loop impedence threshold is required to ensure that the device operates within the required time (0.2 seconds for TN systems). Generally only B type are used in domestic installations, (although C type are permitted).

davelerave

c type shouldb't be needed for this.more suitable for commercial/industrial settings .rcd protection is becomming more prevalent for lighting(transient discrimation may be needed for some circuits)

2011

c type shouldb't be needed for this

I agree.
My point was that it can sometimes open a can of worms!