eGuide - electrical power use instructions
Introduction
Electricity is one of many forms of energy which is governed by precisely defined physical laws.
Electrical energy is produced in power plants at a prescribed standard quality and by means of the transfer and distribution network, is supplied to the end consumer. Many external factors influence electrical energy in the course of its long path with an impact on its final quality.
These factors include
- atmospheric influences (e.g., the effects of lightning),
- influences caused by the use of some electrical appliances (e.g., electronic power and revolution regulators, power sources from electric tools, etc.),
- influences caused by necessary operational manipulations within the network,
- the activity of safeguards and automatic limiters to control network outages,
- frequent switching of large appliances
- mining operations
The above indicated factors may cause
- abnormal amounts of supply voltage (excess voltage, drops or interruptions in supply voltage)
Warning
In keeping with CSN 33 0420, electrical devices installed in NN (low tension) networks must be able to withstand peak pulsed values of up to 6,000 volts.
To avoid damage to electrical appliances due to the effects (overvoltage) of lightning, we recommend equipping both new and existing indoor wiring with voltage overcharge protection. We further recommend disconnecting from the electrical network when thunderstorms are approaching.
Limitation and minimization of the effects of disruptions to the power network on the customer
During disruptions in the distribution network, our first task is to limit the impact of these unpredictable occurrences on the customer to the greatest extent possible. To do so, various safeguards systems are in place whose task is to locate disruptions and disconnect the point of disruption from the power network as quickly as possible.
During this time, there may be changes in the quality of electricity which are dictated by the laws of physics, the nature of the system under use and the network. These primarily concern short-term drops and interruptions in power supply. Once the problem is found, only the area which is directly afflicted will remain without power.
The supplier has the right to interrupt or limit electricity supplies under the contract in the following cases, among others:
- when there is direct threat to life, health or the property of individuals,
- during the occurrence and elimination of outages,
- in carrying out necessary operational adjustments for a maximum of 30 minutes,
- in carrying out planned work.
Coal Services a.s. supplies electrical energy with quality specifications corresponding to EU standards.
The quality specifications for electrical energy are indicated as part of the CSN 50 160 and CSN IEC 38 norms.
Network voltage
The nominal phase voltage in the low tension network is 230 V.
The nominal line voltage in the low tension network is 400 V.
Under normal operational conditions, the tension in the network must be within an allowable tolerance of plus or minus 10%, hence ranging between 207 V and 253 V. 95% of the average effective values for supply voltage measured at 10 minute intervals must be within this tolerance each week.
The rated frequency is 50 Hz. Under normal operating conditions, the supply frequency must be within an allowable tolerance of plus or minus 1% for 99.5% of the year.
Our company does not guarantee the correctness of clock time derived from the supply frequency in the network (synchronous clocks).
The size of deviation from the ideal tension and symmetry is primarily due to the characteristics of the electrical appliances which are connected. Transmission of information and data between customers using the Coal Services a.s. local distribution network is not permitted.
Tri-phase appliances or appliances with greater demands for quality electricity may be connected only if they are safeguarded using appropriate technical means for the limitation of adverse impacts as follows
- loss of voltage of a phase in tri-phase appliances,
- voltage oscillations with appliances sensitive to short-term drops or interruptions in supply,
- changes of frequency for appliances sensitive to these changes.
Our company regularly supplies you with electrical energy of the quality which has been described and which corresponds, as already noted, to European standards. This quality is ordinarily sufficient to allow you to operate and use almost every electrical appliance without problem. For appliances which are especially sensitive to deviations from the nominal voltage value, or appliances used in fields which require increased reliability, incorrect functioning or damage may be avoided only if suitable technical measures are taken.
The following are especially sensitive to overvoltage
- computers, microprocessor controllers, audiovisual technology, lighting regulators, video equipment, satellite equipment, telephone switchboards, fax machines, etc.
The following are especially sensitive to undervoltage
- refrigerators, freezers, automatic dishwashers, etc.
If you are interested in using tools and appliances for which standard quality electrical energy supplies are not adequate (primarily due to overvoltage), we recommend that before purchasing devices of this type, you have the supplier inform you about its sensitivity and resistance and any protective measures.
Conditions for ordinary use of electricity
- With the proper use of safe wiring which conforms to technical norms and safe appliances, electricity is a reliable source of light, warmth and allows other household equipment to function without threatening either health or property.
- Repair and maintenance of wiring and appliances, including portable and extension cords should be entrusted only to a specialist.
- Safeguard appliances and wiring from people with reduced ability to distinguish their danger (babies, mentally disabled people, etc.), by, for example, using socket plugs or switch locks. Protect household pets from electrical shock, as well. (There is a danger, e.g., that they may bite into the cords of electrical appliances.)
- Only purchase and connect safe products to the electrical network.
- Use appliances only for the purpose for which they were designed and in the manner designated in the instructions.
- Appliances and wiring must be protected by appropriate means. The means and implementation of protection must correspond with the appropriate technical norms. Ordinary wiring elements may not be adequate to the demands placed by appliances requiring higher quality electricity.
- Threaded fuses should not be exchanged for stronger fuses or repaired. To do so would threaten your life and those of others.
- During thunderstorms, we recommend disconnecting appliances by unplugging them from the socket.
- WARNING!
Electricity passing through the human body may cause injury or death. Please comply with the above indicated guidelines.
The character of safe products
- The product must be a complete unit. Covers and controls should not be missing nor should they be damaged or loose.
- Portable and extension cords must be of approved design. If they are homemade, do not use them!
- No part of the product may be damaged by heat (kinked, burnt, sooty, etc.).
- Electrical parts of the product may not come into contact with water unless indicated in the instructions.
- See that your electrical wiring has not been overstressed and is checked at regular intervals.
Recommendations for the purchase of electrical appliances
- Make sure that:
- the tag on the appliance indicates 230 V or 230/400 V and 50 Hz,
- the appliance has a tag indicating the manufacturer (name or trademark),
- the appliance is labelled CE or to CCz (CE: the appliance complies with EU directives; CCz: the appliance has been tested in a Czech laboratory and complies with Czech norms),
- the appliance has been equipped with a power cord by the manufacturer. Otherwise, the connection must be done by a specialized firm,
- the appliance is equipped with instructions in Czech
- Safe appliances should be resistant to damage in the event of an interruption in the power supply.
- If you have any doubts about the quality or safety of an electrical appliance, request a declaration of conformity with the requirements of the applicable technical regulations (Law 22/1997 of the legal code on Technical Requirements for Products).
- Store the documentation concerning the purchase, connection and maintenance of the appliance, as well as the wiring, in a safe location.
How to proceed if you suspect an electrical problem
- If your appliance does not function in keeping with your expectations, the cause may not be electrical. Check to see if the appliances connected and if you are using it in accordance with the manufacturer’s instructions.
- If your appliance still refuses to function, find out whether similar problems are apparent with other appliances. If you suspect there is a defect in the appliance, get in touch with a professional electric service technician. Do not tamper with the appliance for the wiring yourself.
- If there is no problem with the appliance or the wiring, get in touch with us – see Contacts.
