Hi All,

I'm planning to install some outside lighting on a soon-to-be new patio
area, and some other places in the garden. There will be a mix of mains
voltage post lights, and some low voltage stuff too.
I wish to use LD11 X10 dimmer modules to control the lights, and was
thinking that the most convenient place to put these would be in an
standard hinged door steel IP66 enclosure outside (in a fairly sheltered
location, in a corner). Cabling to the mains lights would be 1.5mm2 SWA,
and I would like to keep the LV transformers within the same enclosure.

Just wondered if there's any fundamental reason why this setup wouldn't
meet regs in a domestic installation (assuming the actual wiring itself
is all safe and correct etc)?

Thanks,
Ben

In article ,
Ben Willcox writes:
Hi All,

I'm planning to install some outside lighting on a soon-to-be new patio
area, and some other places in the garden. There will be a mix of mains
voltage post lights, and some low voltage stuff too.
I wish to use LD11 X10 dimmer modules to control the lights, and was
thinking that the most convenient place to put these would be in an
standard hinged door steel IP66 enclosure outside (in a fairly sheltered
location, in a corner). Cabling to the mains lights would be 1.5mm2 SWA,
and I would like to keep the LV transformers within the same enclosure.

Just wondered if there's any fundamental reason why this setup wouldn't
meet regs in a domestic installation (assuming the actual wiring itself
is all safe and correct etc)?

Sounds OK to me.
I have an LD11 indoors in a Consumer Unit case. It takes up 4 ways,
and I have a B3 MCB next to it on the basis that it might help
protect the triac if a lamp flashes over at moment of filament
burnout, it's faster than the built-in fuse, and it's dirt cheap
compared with replacing the LD11 (although LD11's have come down
in price since I bought mine). The LD11 is a nice item, with
gradual dim up and down on both the manual switch and X10 control.
I do not have anything which can send the "extended" X10 commands,
so I don't use that feature of it.

Watchout for heat dissipation. The LD11 doesn't generate much
noticable background heat, but the triac will necessarily generate
something like 1W heat per 200W of load. The LV transformers will
also generate heat. Allow for this when choosing a box, and don't
go for the smallest size with everything crammed in tightly. If
you are using multiple LD11's, I would suggest leaving one way
spare between them (or occupied by MCB which generates negligable
heat at low currents). You could also include a thermostat in the
box set to, say, 40C to cut the power to the box if it does get
too hot.

Also, you'll need to do some checks on the earth fault loop
impedance and voltage drop on your 1.5mm² cable. This shouldn't
be an issue if protected at 6A unless it's very long (sorry don't
have the OSG on me to look up max length). If the LV runs are of
any appreciable length, they will need to be thicker cable to
avoid significant voltage loss.

--
Andrew Gabriel

Another comment I should have made...

An outdoor cabinet containing electronics is going to need some
protection against internal condensation. Typically this is
provided by a combination of ventilation, spacing the electronics
away from the sides where condensation forms/runs, protected from
drips from internal top surface, drain holes so the condensation
which forms can escape, and possibly provision of a low power anti-
condensation heater.

IP66 is probably OTT, and difficult to meet the anti-condensation
issues. You could probably go down as low as IP34, unless you plan
on directing firehoses at it.

--
Andrew Gabriel

Andrew Gabriel wrote:
An outdoor cabinet containing electronics is going to need some
protection against internal condensation. Typically this is
provided by a combination of ventilation, spacing the electronics
away from the sides where condensation forms/runs, protected from
drips from internal top surface, drain holes so the condensation
which forms can escape, and possibly provision of a low power anti-
condensation heater.

IP66 is probably OTT, and difficult to meet the anti-condensation
issues. You could probably go down as low as IP34, unless you plan
on directing firehoses at it.

Thanks Andrew, didn't see your post until just now. I had been planning
to use something like this:

http://uk.farnell.com/productimages/...d/42271076.jpg

as I already have one left over from another project. I hadn't
considered the condensation issue, so maybe I should look for a
different type of enclosure...?

Cheers,
Ben/

http://uk.farnell.com/productimages/...d/42271076.jpg

as I already have one left over from another project. I hadn't
considered the condensation issue, so maybe I should look for a
different type of enclosure...?

Nothing that a drill and hacksaw couldn't sort out!

I'd put a few carefully chosen gratings in it for ventilation. You know the
type, with the slots angled downwards to prevent water entry during rain,
but providing plenty of air circulation. Drainage holes in the bottom.

Christian.

Ben Willcox wrote:
I'm planning to install some outside lighting on a soon-to-be new patio
area, and some other places in the garden. There will be a mix of mains
voltage post lights, and some low voltage stuff too.
I wish to use LD11 X10 dimmer modules to control the lights, and was
thinking that the most convenient place to put these would be in an
standard hinged door steel IP66 enclosure outside (in a fairly sheltered
location, in a corner). Cabling to the mains lights would be 1.5mm2 SWA,
and I would like to keep the LV transformers within the same enclosure.

Just wondered if there's any fundamental reason why this setup wouldn't
meet regs in a domestic installation (assuming the actual wiring itself
is all safe and correct etc)?


OK well I've had no objections, so I guess it sounds OK! My next
question would be, what would be the preferred method of mains supply to
this setup, given that I have a few options:

1) Run feed from existing internal lighting circuit (non-RCD protected)
2) Run new feed from CU on RCD-protected side
3) Run new feed from CU on non RCD-protected side but fit an RCBO
4) Run feed from existing internal lighting circuit and include a
separate RCD in the IP66 box

AIUI an RCD is not be mandatory, but might be a good idea? Im thinking
option 4 might be best.

Ben.

Just wondered if there's any fundamental reason why this setup wouldn't
meet regs in a domestic installation (assuming the actual wiring itself
is all safe and correct etc)?

It sounds close to best practice to me, provided any ventilation
requirements are met. The dimmer units can run quite hot.

OK well I've had no objections, so I guess it sounds OK! My next
question would be, what would be the preferred method of mains supply to
this setup, given that I have a few options:

1) Run feed from existing internal lighting circuit (non-RCD protected)

OK.

2) Run new feed from CU on RCD-protected side

No. I would not share outdoor circuits with RCDed indoor circuits.

3) Run new feed from CU on non RCD-protected side but fit an RCBO

Excellent.

4) Run feed from existing internal lighting circuit and include a
separate RCD in the IP66 box

Good.

AIUI an RCD is not be mandatory, but might be a good idea? Im thinking
option 4 might be best.

An RCD is a good idea, provided that the lights aren't safety critical. Not
essential, though, unless the house is TT earthed. I'd use a 100mA one,
though, to avoid nuisance trips, unless the circuit is dual purpose and
supplies sockets etc.

Christian.

Hi, Im setting up some outdoor lighting myself in the next few weeks.
Just looking at what was written in regard to how to connect the
outdoor lighting to your existing circuits and wondered if anyone can
answer a couple of questions:

1) Run feed from existing internal lighting circuit (non-RCD protected)

OK.

From what I understand its best to protect outdoor electrics using an
RCD. Why is this an OK solution?

2) Run new feed from CU on RCD-protected side

No. I would not share outdoor circuits with RCDed indoor circuits.

Whats the reason behind this?

4) Run feed from existing internal lighting circuit and include a
separate RCD in the IP66 box

Good.

Not exactly sure how the previous owners have got it set up in my
house. I already have an external light but not sure if this is wired
to the lighting circuit or the downstairs ring which is RCD'ed. Ive got
a feeling the latter is true (and some simple testing will confirm the
theory).

So is it better for me to extend my existing lighting circuit to
accomodate the downstairs lights or if not possible what can I do to
make a safe installation using the existing indoor RCD'ed circuits?

The proposed lighting is 6 LED walk over fittings to be recessed into a
patio and two wall lights to replace the current halogen spot light.

The current halogen wall light is switched inside. What Id like to do
is make this a double switch - 1 switch for the floor level lighting
and the other switch for the wall lighting.

I need to understand that if this is currently a spur from the existing
lighting circuit or the ring main how I can effectivly control two
installations from the one spur. As I understand it should be one spur
per fitting??

Cheers,

CM.

From what I understand its best to protect outdoor electrics using an
RCD. Why is this an OK solution?

Basically, because there's next to no chance you'll get electrocuted by most
light fittings. I'd be more concerned if the light fittings are largely
metallic and not double insulated. I would generally say it was preferable
to RCD outdoor lighting, but is rarely essential. Note that TT earthed
installations always require an RCD, but there are methods to reduce
nuisance tripping.

No. I would not share outdoor circuits with RCDed indoor circuits.

Whats the reason behind this?

Because outdoor circuits are subject to moisture that can cause nuisance
tripping. When this occurs, it is best that it doesn't turn off all your
sockets, taking out your computer, TV and even fridge/freezer in some cases.

So is it better for me to extend my existing lighting circuit to
accomodate the downstairs lights or if not possible what can I do to
make a safe installation using the existing indoor RCD'ed circuits?

It would be OK on the lighting circuit, but best on its own circuit. It is
not possible to modify the indoor RCD circuit to remove the possibility of
the outdoor circuits providing nuisance trips.

I need to understand that if this is currently a spur from the existing
lighting circuit or the ring main how I can effectivly control two
installations from the one spur. As I understand it should be one spur
per fitting??

No, this would be fine. The lighting circuits need to be off a fused
connection unit, as lighting circuits must normally be fused at 10A or below
(some fittings must be 6A or below). Normally, you would use a connection
unit with a 5A fuse. This can then drive the dual gang switch, which should
either be DP (preferable) or have the neutrals looped at the switch. You can
then switch to suitable outdoor cable (i.e. SWA/XLPE/HiTuf) and run to the
light fittings. If you must run the lighting off an RCDed socket circuit
(knowing the risks), then definitely use DP switches, as some types of
faults are neutralearth. The DP switches will isolate the exterior lights,
meaning you can turn the house power back on, even without clearing the
fault (which might require sunny weather).

Your existing setup probably uses a switched FCU. If so, I'd replace this
with an unswitched unit and then feed into a dual gang DP switch. There's no
requirement for DP, but it is (very marginally) safer, and, more
importantly, provides an easy method to loop the neutrals without requiring
crimping or additional terminals floating around.

Christian.