Before purchasing a house, it is essential to check the Electrical Capacity. A watt is the unit of electrical power, and watts are equivalent to volts times amps (W=V x A). In older houses, if the electrical service has not been upgraded, the electrical service capacity is likely 30 and 60 amps at 110 or 110/220 volts. Any service less than 60 amps at 110/220 volts is considered inadequate. Generally, homeowners with such electrical service, who have lived in that house for over 40 years and have found the service totally acceptable.
However, while that might be true for them because they adjusted to the lower electrical capacity by not using any major electrical appliances, the service must be upgraded. The electrical service capacity should be great enough to support the power requirements of the various appliances.
There are numerous electrical appliances available to the homeowner, and the minimum electrical service is 100 amps at 110/220 volts. Still, if the house is small and the homeowners do not use many electrical appliances, 60 amps at 110/220 volts will likely be enough. But when a house is equipped with an electric water heater, electric range, electric clothes dryer and a central air conditioning system, it should have at least 150-amp service. Moreover, if electric heat is added to the above appliances, the house should have 200-amp service.
Electrical Capacity
Capacity is an inherent property in electrical circuits, and plays an essential part in the amount of current. All conductors will absorb and hold a certain quantity of electricity, and one of the simplest illustrations of this is the Leyden jar. When the terminals to a Leyden jar are connected to the leads of a strong generator, a certain amount of current appears to flow into the jar and become absorbed. A common experiment is to “charge” these jars and discharge them at will by touching the terminals altogether.
Capacity refers to this ability to store electricity, and a number of things beside electric current used in the charging contribute to the capacity. As inferred from the experiment with the Leyden jars, the larger the jar – implicitly, the larger the tin foil – the greater the capacity. When it comes to the voltage of the charging device, the greater the voltage, the higher the saturation. Then, the composition of the medium used as an insulator between the metallic surfaces of the condenser must be taken into consideration also, as well as the distance one of these metallic surfaces is from the other – meaning the thickness of this insulating medium.
However, the thickness of the metallic substance is not a factor in the capacity, as it is believed that the electricity is not held in the metal itself, but is stored upon the insulating medium used in building the condenser. To prove this, you can construct a simple condenser of two tin plates and a piece of glass. After charging, remove the plates with an insulated handle. There will not be any manifestation of electricity until they are returned to the original position. Considering this to be the case in all condensers, it can be easily presume that the capacity is proportional to the area of the conductor and not its volume.
In low voltage work, where the voltage is less than will cause a spark to jump through a thin insulating medium, paraffine waxed paper serves successfully as condenser material, not just due to its great insulating qualities, but also because of the large surfaces of metal that can be brought close to one another without touching. To obtain the maximum capacity with a minimum expense and bulk, most of the condensers available in the market are made of paraffine paper and the thinnest tin foil. The best standard condensers, however, are made of mica sheets and metal foil, but are far more expensive than the paraffine paper ones.
On the other hand, considering the subject of condensers to be connected for capacity affects across a circuit of high voltage, such as the secondary of an induction oil, waxed paper will never do, as it would puncture at the very first discharge.