size of wire for outdoor lighting

[Fat Prophet]

I am installing outdoor lights around my house. The total length is 2 circuits of 50 meters each, with maximum of 3 lights of 30 Watts or less on each circuit. My options for wire seem to be IEC 53 VCT2x1.0sq.mm and IEC 53 2x1.5sq.mm. There will be one on/off switch on each circuit. I assume that the 2x1.0 sq.mm. is (more than) adequate for a load of 90 Watts or less.  Am I correct? Thanks for any help/guidance. F.P. 

[Crossy]

1mm should be fine, however many will recommend 1.5 simply because it's physically more robust and easier to terminate into the fittings.

 

Will you be running in conduit? VCT isn't rated for outdoor use (although it does seem to survive well), the "proper stuff" is NYY which is waterproof and can be buried direct in ground.

 

Either way make sure the circuit is protected by an RCD/RCBO.

 

[Fat Prophet]

Thanks. A few videos that I have seen say that if the run length is more than 50 feet (obviously a US video) a higher voltage wire should be used. I also saw one good video that recommended 12-2 gauge wire for outdoor lighting with up to 20 4 WATT LED lights, which translates into about 2mm diameter:

American Wire Gauge (#AWG)	Diameter (inches)	Diameter (mm)
12	0.0808	2.05

The 1.5 is a bit under 12-2 gauge, so I think I will opt for the larger 1.5 mm diameter to be "safe". Thanks. 

[kamalabob2]

There is so little difference in the selling price, you might consider the 1.5 sq mm VCT.  Voltage drop at your supply is a factor that is hard to control. VCT is a fine cable for exterior in the right conduit, but never buried. Yellow conduit and white conduit are not to be exposed out of doors. Metal conduit and HDPE black conduit with a red stripe are available in any decent electric shop. 

[Fat Prophet]

3 minutes ago, Crossy said:

1mm should be fine, however many will recommend 1.5 simply because it's physically more robust and easier to terminate into the fittings.

 

Will you be running in conduit? VCT isn't rated for outdoor use (although it does seem to survive well), the "proper stuff" is NYY which is waterproof and can be buried direct in ground.

 

Either way make sure the circuit is protected by an RCD/RCBO.

 

Thanks. I will put the wire in conduit, but I want an outdoor rated wire. I will look for NYY.

[Fat Prophet]

1 minute ago, kamalabob2 said:

There is so little difference in the selling price, you might consider the 1.5 sq mm VCT.  Voltage drop at your supply is a factor that is hard to control. VCT is a fine cable for exterior in the right conduit, but never buried. Yellow conduit and white conduit are not to be exposed out of doors. Metal conduit and HDPE black conduit with a red stripe are available in any decent electric shop. 

The wire will be buried along the exterior wall. I have seen a lot of the yellow conduit buried, and had no idea that it wouldn't be suitable to be buried. I will look for the black conduit.

[wayned]

I would run 2.5mm².  It's an overkill for now but you never know what you might want to do in the future and at least you will have the wire size to add additional load. I've built a few houses in my life and adding additional circuits can be a problem if the current wire size won't support the additional load.  I have even coiled wire in hollow walls so that I add additional fixtures by cutting the mounting hole and reaching in to get the wire.

[Fat Prophet]

9 hours ago, wayned said:

I would run 2.5mm².  It's an overkill for now but you never know what you might want to do in the future and at least you will have the wire size to add additional load. I've built a few houses in my life and adding additional circuits can be a problem if the current wire size won't support the additional load.  I have even coiled wire in hollow walls so that I add additional fixtures by cutting the mounting hole and reaching in to get the wire.

Thanks, a great post. I have had the same idea of coiling some wire in a utility box to allow for additional lights to be added later. But my yard is very small, only a border around the house, so there is little benefit to more than 2 additional lights in the future. I will use the 1.5mm² wire and try to find a place to coil some extra wire. Thanks...

[Fat Prophet]

8 minutes ago, Arjen said:

I agree fully with this. 

 

I pulled cables to our pond, for just a few LED lights. I used 1.5mm². Now I regret this, as there are also pumps running on the same cable. It works, but I am at the border from what is possible....

 

Arjen.

Thanks. I have a very small land plot, only 335 m² and a house (2 stories) of 235 m². So, there just isn't much that I can do with the new circuit other than lights, and 7 lights (5 or 6 for now) is adequate, just to light the walkway.  There is a small swimming pool in the front of the house with its own separate circuits for the pump and underwater lights. This is already installed. The 2 sides and rear of the house have a 2 meter border from the house to the boundary wall -- I plan 1 light in each rear corner, and one in the back middle to light the walkway; in the front will be 1 light in the corner and 1 flood lite shining into a coconut tree near the pool for aesthetics. I purchased a 30 Watt LED flood lite for the coconut tree, and 6  1 meter tall post lamps (2 extra for the future) for around the house.  There is no space for a pond, tennis courts or anything else for that matter. So, I am sure that 1.5 mm² will be adequate, for now and the future. I am now most concerned about ensuring that the wire and conduit can be buried in the ground, which is a must. I will look for the NYY cable and the black conduit with the red stripe. I hope that will suffice. Thanks again. FP

[Fruit Trader]

Volunteer job last year at local temple, up-lights at trees some street lights on wall and poles.

 

All wired using NYY 2 x 1.5 inside 20mm HDP conduits back to above ground junction boxes. We used vacuum cleaner to suck draw cords into HDP conduit which are used to pull in the NYY cable.  

 

[Fat Prophet]

1 hour ago, Fruit Trader said:

Volunteer job last year at local temple, up-lights at trees some street lights on wall and poles.

 

All wired using NYY 2 x 1.5 inside 20mm HDP conduits back to above ground junction boxes. We used vacuum cleaner to suck draw cords into HDP conduit which are used to pull in the NYY cable.  

 

Excellent. Thanks.