What is water and dust protection IP level

IP marking standard refers to the water and dust protection level which is determined by IEC(International Electronic Commission)
The code is divided into 3 parts, the first number (dust protection), the second number(water protection), and the third letter (protection against hazardous components).

1. First letter (dust)

Level	Object size protected against	Effective against
0	—	No protection against contact and ingress of objects
1	>50 mm	Any large surface of the body, such as the back of a hand, but no protection against deliberate contact with a body part
2	>12.5 mm	Fingers or similar objects
3	>2.5 mm	Tools, thick wires, etc.
4	>1 mm	Most wires, screws, etc.
5	Dust protected	Ingress of dust is not entirely prevented, but it must not enter in sufficient quantity to interfere with the satisfactory operation of the equipment.
6	Dust tight	No ingress of dust; complete protection against contact (dust tight)

2. Second Letter (water)

Level	Protection	Test method
0	—	No protection
1	Dripping water	10 mins of 1 mm rainfall
2	Dripping water at 15° tiled	10 mins of 3 mm rainfall tiled 15°
3	Spraying water	5 mins of 0.7 litre per minute water
4	Splashing water	5 mins of 10 litre per minute water
5	Water jets	3 mins of water jet at 12.5 litre per minute
6	powerful water jets	3 mins at 100 litre per minute
7	1m immersion	30 mins at 1m below surface
8	immersion beyond 1m	test at 3m or deeper constantly
9k	high temperature/pressure water	16 litre per minute of 10,000Pa water at 80C

3. Other hazardous protection

Letter	Meaning
f	Oil resistant
H	High voltage device
M	Device moving during water test
S	Device standing still during water test
W	Weather conditions

how to install T8 LED from normal T8 fluorescent with electronic/ magnetic ballast

1. remove the fluorescent tube from the fixture

2. Remove the starter

3. open up the lid of the fixture

4. unscrew the ballast

5.remove the ballast

6. connect the wire directly to the poles of the fixture

7. install led tube onto the fixture

Finish

LED Knowledge database links

http://pantip.com/topic/33958522

Light Colour and Their application

According to Hatariled 

2200K is super warm white

2700-3000K is warm white

3500-4500K is beauty white

5500-6500K is cool white

above 6500K is super cool white (not recommended)

Light colour as seen by human eye can be classified by many systems. One of the most used system is the Colouring Rendering Index which is supported by the CIE (International commission on illumination). This system correlation the colour with black body radiation spectrum since most natural light sources such as sunlight are produced by black body.

In every day use, light colour has an incredibly large influence over human emotions. A lot of research has been done to show that at the lower end of the spectrum where the warm white products took reference makes human feel more hungry, sleepy and relaxed. The application is obvious but how do you know how warm is warm. This will we explained on the next page.