The lumen (symbol: lm) is the unit of the International System of Units to measure the luminous flux, a measure of the light power emitted by the source. The luminous flux of radiant flux difference that the former provides the variable sensitivity of the eye to different wavelengths of light and the latter involves all electromagnetic radiation emitted by the source according Wien law and Stefan-Boltzmann regardless of whether such radiation is visible or not. 1 lm = 1 cd. sr = 1 lx. m2

hen we talk about IP code (International Protection) we talk about an international standard (IEC 60529) which classifies the protection against external factors, solid or liquid, that has a component or electronic device; LED strips, controllers, meters, security cameras, etc.

This alpha-numerically standard has been designed to sort different levels of protection. Nomenclature starts with IP followed by two numeric values.

- Example IP68:

The first value ranges from 0 to 6 and indicates the protection against solid agents. In this case, strong protection against dust.

The second value is between 0 and 8 and indicates the protection against liquid agents. In this case the complete and prolonged immersion during the time specified by the manufacturer.

We could say that the larger the number is greater IP protection has a device.

In below table, we can see different IP protections levels available.

IPXX	First digit (IPxx)	Second digit (IPxx)
0	Unprotected.	Unprotected.
1	Protection against objects of> 50 mm diameter.	Protection against vertically dripping water.
2	Protection against objects of> 12.5 mm diameter.	Protection against inclined drip water up to 15°.
3	Protection against objects of> 2 mm in diameter.	Protection against water projected from any direction, up to 60°.
4	Protection against objects of> 1 mm in diameter.	Protection against splashing water any direction.
5	Ingress of dust is not entirely revented, but it must not enter in sufficient quantity to interfere with the satisfactory operation of the equipment .	Protection against water jets.
6	Dust tight.	Protection against strong jets of water.
7		Protection against complete immersion up to 1 meter for 30 minutes.
8		Protection against complete and prolonged immersion.

When carrying out an electrical installation or electrical circuit several factors must be taken into account, one of them is the selection of the appropriate cable. According to the installation and the use of the same we can find different diameters that support different loads. The cable section will also help us not to overheat our installation, since the larger the section, the greater the thermal resistance.
In the following table poWe can see the corresponding load supported for the different sections of cables.

As it is common in installations we can find a standard of colors in the electric cables.

These regulations help at a glance to understand the connection and the resolution of possible faults or failures.

Below we attach the color/cable relation for electrical installations.

1. The ground wire can be identified in several ways:
• Green cable.
• C cablegreen smell with a yellow line.
• Cable without insulation.
2. The neutral wire will be blue.
3. The phase cable can be identified in several ways:
• Any color different from neutral or earth.
• Black insulation.
• Brown isolate.
• Gray insulation.

The insulating or insulating tape is a fundamental element when making a repair or performing an electrical installation. The insulating tape will help us to protect and insulate the electrical cables from possible crossings or contacts between them or with other elements, guaranteeing that the connection is well insulated avoiding possible short circuits.
Its use is very simple, since being a flexible material allows us to apply it with comfort.
To achieve a perfect union, it is recommended that we wrap the tape covering half the cable and half over the joint, stretching the tape slightly while rolling obliquely.

• For the ground wire, colored insulation tape will be used:
• Green.
• Green with a yellow line.
• For the neutral cable, blue insulating tape will be used.
• For the cable the phase isYou can use any other color:
• Any color different from neutral or earth.
• Black insulating tape.
• Brown insulating tape.
• Gray insulating tape.

VAC would be the abbreviation of Volt Altern Current which would be translated Volts of alternating current. The difference between VDC is that its sinusoidal oscillation achieving a more efficient energy transmission.

The alternating current is the energy that we receive in our homes, it is generated in the power plants by means of alternators.

The intensity of this type of current varies with time, and changes direction 50 times throughsecond (50hz). The generated voltage changes in the form of sine wave so it is not constant.

In the image:

1. Current by pulsations.
2. Direct current (DC).
3. Alternating current (AC).
4. Variable current.