At design of the scheme of the new electrical wiring or capital repairs existing for determination of necessary section of a wire it is necessary to calculate correctly the maximum load current in the power supply network. It can be done by simple calculations.
It is required to you
- calculator
Instruction
1. Count, proceeding from quantity, the area of rooms and their appointment, quantity and type of lighting fixtures load current in lighting network. For this purpose use a formula P=pS where p is the specific power of lighting, measure in Watts on metr2 (on average - 20 Watts), S – room space. Example: there are 5 rooms of 120 square meters. Power is equal: 20×120=2400 Watts. Calculate load current in lighting network: 2400:220 = 10.9 Ampere.
2. Calculate the maximum power of at the same time switched on devices in each room. On average this indicator does not exceed 900 Watts for living rooms. If in winter time oil heaters for heating are used, too consider their power. Pay special attention to kitchen: the majority of power-intensive devices to be exactly there. At simultaneous turning on of the 3000 Watts 3500 Watts modern electric cooking stove, the built-in oven, the 1400 Watts microwave, 2000 Watts electric kettle, washing machine (many people have washing machines in kitchen) 2200 Watts, the 400 Watts 1000 Watts fridge, the food processor (such situation can arise by preparation for some family celebration), load current will rise to: 3000+3500+1400+2000+2200+400+1000=13500:220=61.5 Ampere!
3. At the insufficient section of a wire the simultaneous turning on of these devices will lead to emergency shutdown of the electric power at the most inappropriate moment. Plus the electric water heater in the 1000 Watts bathroom. Also enter 15 percentage power reserve into calculation. In our case the maximum load current turns out: about 11 Amperes on lighting + on 900 Watts on 5 rooms = 4500:220=20.5 Amperes of the maximum consumption in living rooms + 61.5 Ampere in kitchen + 4.5 Ampere in the bathroom = 97.5:100×115=112 Ampere.