Hundreds of identical-looking surge protectors and extension cords on store shelves sometimes baffle. What to choose, filter or extension cord? What manufacturer, with what characteristics? We will deal with the selection criteria for these, sometimes simply necessary, devices.
The basis of any surge protector and extension cord are the elements of the plug connection. Plug ( from the German Stöpsel – “plug” ) connection consists of a plug and a socket. The main part at the plug is pin contacts, at the socket – contact sockets. You can combine these elements in different ways: there are about twenty types of plug connectors used in the world.
On the territory of the Russian Federation, four types of connectors are used.
Type C sockets accept CEE 7/16 plugs and old Soviet style plugs. The diameter of their pin contacts is 4 mm. Phase voltage is suitable for them. The rated current for the CEE 7/1 6 plug is 10 A.
Type F sockets are designed to accept a CEE 7/7 plug . To the usual pair of phase voltage contacts, a third ground contact is added here. The rated current for the CEE 7/7 plug is 16 A.
The pins of the plug are 4.8 mm in diameter, which means that they cannot be plugged into a Type C socket . Attempts to push the plug into such a socket are fraught with breakage of the outlet.
Connecting a CEE 7/16 plug to a type F socket may cause overheating and burning of the socket contacts. The reason is simple: loose fit of thinner pin contacts.
Due to the large number of CEE 7/16 plugs consumers have , surge protectors are supplemented with a socket of the appropriate type.
To reduce overall dimensions, filters are often equipped with a GP socket . The outlet got its name from the English Gadget Parking – “parking for gadgets”.
Two lateral pairs of holes with contacts can simultaneously connect two CEE 7/16 plugs at once . Instead, a CEE 7/7 plug can be inserted into the central pair of holes . This pair of contacts is usually supplemented with ground contacts.
The last, fourth type of plug connector is IEC C13 / C14 , consisting of an IEC C13 socket and an IEC C14 plug .
This type, also called “computer”, is used when connecting a surge protector to an uninterruptible power supply (UPS) .
Choosing a network filter
First, answer the questions, the answers to which you do not doubt. Consistently exclude those answers that clearly do not fit.
From practical advice for those undergoing testing
This approach is also applicable to the choice of network filters . First, we determine the technical characteristics, without which the device does not make sense to buy. Then we move on to more complex and subtle aspects.
The first stage of selection
How to connect a surge protector to a power source.
CEE 7/7 plugs are used to connect line filters to the mains . They belong to the Schuko system ( from the German Schutzkontakt – “protective contact”) . Together with sockets type F and GP they guarantee protection against electric shock.
Surge protectors are connected to uninterruptible power supplies with an IEC C14 plug , which also has a protective grounding contact. When buying a surge protector for a UPS, this is a key point. By selecting the desired network connection option, we significantly narrow the search field.
It is necessary to calculate in advance the number of devices connected to the network filter. So we will determine the number of power filter outlets. It is worth considering a small margin for the future: what if you have to connect something else?
For example, in search of a surge protector for 12 outlets, we find only two gadgets in the catalog.
Surge protector Qumo Power Tower Pro black
3 299 ₽ *
Surge protector Tessan TP-VA5U12E black
5 299 ₽ *
The choice is not very large – so let’s focus on the more common surge protectors with five outlets. Then it remains only to deal with other characteristics of these filters – and make a decision.
It is necessary to calculate the total power of operating consumers. There are two options here. Or all devices connected to the filter are involved. Or only some of them are connected at the same time.
Let’s compare the power of our devices with the capabilities of network filters.
Our first step narrowed down the number of models to consider from 212 to 48. The task of choosing the right network filter was made almost five times easier.
The second stage of selection (main)
At this stage, you have to make the main choice – to decide on the type of protection for the surge protector.
According to the degree of protection, network filters are usually divided into three conditional groups:
A basic level of;
Our pre-selected 48 filters have the following types of protection:
All models provide protection against impulse noise that may occur in the electrical network. To do this, in the simplest basic version, the filter is equipped with a varistor.
In addition to the varistor, thermal fuses are also installed on the base level filters. This is where all the protection capabilities of the base-level filters end.
Filters with an advanced level of protection protect not only from impulse, but also from high-frequency interference. To do this, they are equipped with an additional LC filter.
Filters with a professional level of protection extinguish almost all interference. They are worth buying for expensive noise-sensitive equipment. Such models are more expensive, but their reliability fully pays for the costs.
Reusable thermal fuses are installed in such filters. In addition, they provide reliable protection of connected equipment from lightning strikes, power surges and impulse noise with a maximum leakage current of up to 120 A.
At the final stage, let’s pay attention to the features of the filter controls – and the safety of working with them.
Switches in network filters can be either single-pole or two-pole.
Filters with a two-pole switch are the best choice. They are usually wider than single-pole and completely de-energize the filter. A single-pole switch can turn off the neutral line, leaving the second one energized. It all depends on which side of the plug is connected to the wall outlet.
Most filters come with one common switch, but there are gadgets with switches for each outlet.
The passive protection system is important for families with young children. On some models, it is implemented by installing protective shutters on sockets, on others – special plugs.
All models have indicators informing about the inclusion of the surge protector. Often they are combined with a switch button.
There are models with an indication of the presence of grounding. And this is a very useful option, since you only need to connect the surge protector to an outlet with a ground wire.
Some filters have indicators that inform you about the overload of the gadget by the power of the connected devices.
USB ports and GP sockets
The presence of USB ports provide a direct connection of gadgets to the mains. And with GP sockets, the filters become more compact.
The extension cord looks very similar to a surge protector. It performs the same role – a socket on a wire. But an extension cord, unlike a surge protector, does not suppress impulse noise and does not protect equipment from sudden power surges.
At the same time, many extension cords are produced in a simplified version – without a third ground contact.
Extension cords do not have power overload protection. Therefore, it is very important to carefully select the device according to this indicator. The electrical safety of the extension cord is the main criterion when choosing.
When choosing an extension cord, three indicators should be mutually linked:
maximum load current of the extension cord;
minimum cross section of copper conductor;
maximum power of connected devices.
Typically, the manufacturer indicates the maximum load current of the gadget and the maximum power of the connected devices. The latter, however, can be determined by yourself. It is enough to multiply the values \u200b\u200bof the maximum load current and voltage in the network (10 A x 220 V \u003d 2200 W).
By the way, in this way you can determine the maximum power of devices that can be connected to a power outlet.
The cross section of the wire can be found on its marking. Conscientious manufacturers indicate it without fail.
Extension cords are available in household and power versions.
For household extension cords , the length of the cord usually does not exceed 10 meters.
Power extension cords are designed to connect more powerful devices. The length of their cord can reach 50 meters. Therefore, there are models in which the cable is wound on a reel for convenience.
Often, power extension cords are used outdoors. Therefore, they must have enhanced protection against external conditions: for example, double cable insulation.
Sockets of power extension cords designed for operation in dusty conditions have special protective covers.
Some models are equipped with a general switch and a multiple-acting thermal fuse. Other things being equal, such extensions are preferable.
Choice of splitter and adapter
When you need to plug several devices into a power outlet at the same time, a splitter is useful .
There are several output sockets on the splitters – from two to five.
The plug of the splitter and output sockets can be with or without a third grounding contact.
The maximum load current of the splitter is always indicated on the case. Knowing the voltage in the network, you can easily determine the maximum power of the connected devices.
Many models of tees are equipped with protective shutters.
If the plug of the household appliance does not fit the existing sockets, adapters will help you .
Selecting an outlet block
A variety of network filters are socket blocks . They are compatible with 10” and 19” form factor cabinets and racks designed for the installation of telecommunications equipment. Such modules are supplied with a common switch for all sockets. Of course, with a built-in indicator light and fuse. The latter turns off devices in case of overvoltage or short circuit.