Charleston Cobra Nautilus – Underwater Spot Light (Solid Brass)

Garden Lighting Made Easy!

Lumena offer a large range of high end 12v Plug and Play lighting and accessories making it very simple and easy for quick DIY installation. Low voltage lighting is particularly suited to outdoor environments because it tolerates the damp conditions without performance being affected. Anything required underwater should also be low voltage as it is much safer.

When it comes to connections, there are multiple cables and adaptors which are suitable for various 12v plug and play lighting systems. Lumena’s Versa plug & play system is compatible with a number of brands such as Techmar. Cables are available in various length in various combinations of plug & play and open end. In addition, 3 way and 6 way connectors make it very simple for connecting components and fittings to just one transformer.

12v lightings requires a transformer in order for these to be powered. A transformer converts 240v mains down to 12v low voltage. We stock various wattage transformers (10w, 20w, 50w and 100w). Calculate which size transformer is required for a circuit following this simple formula:

Lamp Wattage x Lamp Quantity = Total Wattage Required (minimum)

Example: 5W MR16 x 3 fittings = 15W    (20W transformer required)

You must never exceed the wattage of a transformer, and avoid underloading. The ideal capacity is 75-90% load.

12v Lighting Set-up Example

12v lighting circuits can use a combination of plug and play and hard wired components. Versa Plug & play is simple with various compatible adaptors, cables and transformers available. Easily convert plug and play to hard wired with our plug & play to open ended cable. Standard junction boxes and in-line connectors can then be used to connect the two systems together.

What is voltage drop?

The term ‘Voltage Drop’ relates to the amount of voltage loss that occurs through all or part of a circuit. This is a result of increased resistance which is a measure of the opposition to current flow in a circuit, measured in ohms (Ω). Electrical cables of any size and length carrying current always present resistance. Although it can affect the entire circuit, it is first apparent at the end of a cable run. A simple comparison would be a garden hose, where the pressure of water running through it reduces the further away it is from its source.

What causes voltage drop?

The 4 main factors which contribute to voltage drop are cable length, wire temperature, wire material and the cross sectional area. Generally, 12V lighting systems can withstand a maximum voltage drop of up to 8% (1V) with no noticeable effects, on the basis that the correct cable / power source is used and it is within range of the LED lamp voltage. If significant voltage drop does occur, it can cause dim lighting, strobing or no power at all.

How to reduce voltage drop

To reduce the risk of voltage drop, consider the following:

• Reduce cable runs – keep length to a minimum with no more than 12 fittings per circuit
• Highly conductive wire, e.g. copper. A tinned end can improve performance and longevity
• Use high quality, heat resistant rubber cable. Minimum H05RN-F
• Use thicker cable where possible (1.5mm² / 2.5mm²) with a secure, watertight connection

For a larger garden where this is not possible, consider laying a mains power feed to various points / areas where additional 12V transformers can be installed to create separate, smaller circuits. 240V fittings can also be connected to the mains feed if required.

Voltage drop cable run guides

Suggested maximum cable run includes cable supplied with each fitting, adaptors and connector cables. Where longer cable runs are required, use thicker cable such as 1.5mm² / 2.5mm² which have a lower resistance and reduce voltage drop. Cable runs can be increased by up to 50% (approx.) when thicker cable is used.

For longer cable runs, thicker cable is recommended. The below table is for 1.5mm and 2.5mm 2 core cable.

The above tables are a guide only. We strongly recommend that the voltage is checked with a volt meter at each fitting prior to final placement. Some external factors can affect performance, such as placement of cable etc.