Power strip
Typical housing styles include strip, rack-mount, under-monitor and direct plug-in.
[3][4] This reduces the consumption of standby power used by computer peripherals and other equipment when not in use, saving money and energy [5] Some more-sophisticated power strips have a master and slave socket arrangement, and when the "master" socket detects standby mode in the attached appliance's current it turns off the whole strip.
A different power strip design intended to save energy uses a passive infrared (PIR) or ultrasonic sound detector to determine if a person is nearby.
It is recommended that appliances that need a controlled shutdown sequence (such as many ink-jet printers) not be plugged into a slave socket on such a strip as it can damage them if they are switched off incorrectly (for example the inkjet printer may not have capped the print head in time, and consequently the ink will dry and clog the print head.)
Socket arrangement varies considerably, but for physical access reasons there are rarely more than two rows.
Since MOVs degrade somewhat each time they are triggered, power strips using them have a limited, and unpredictable, protective life.
Some power strips have "protection status" lights which are designed to turn off if protective MOVs connected to the live wire have failed, but such simple circuits cannot detect all failure modes (such as failure of a MOV connected between neutral and ground).
The surge-induced triggering of MOVs can cause damage to an upstream device, such as an uninterruptible power supply (UPS), which typically sees an overload condition while the surge is being suppressed.
More-elaborate power strips may use inductor-capacitor networks to achieve a similar effect of protecting equipment from high voltage spikes on the mains circuit.
These more-expensive arrangements are much less prone to silent degradation than MOVs, and often have monitoring lights that indicate whether the protective circuitry is still connected.
In the European Union, power strips with surge suppression circuits can demonstrate compliance with the (LVD) Low Voltage Directive 2006/95/EC [8] by complying with the requirements of EN 61643-11:2002+A1.
Likewise, power strips with telecoms surge suppression circuits can demonstrate compliance with the LVD by complying with the requirements of EN 61643-21:2001.
However, due to manufacturing variations between the MOVs, the surge energy will not be spread evenly, and will typically go through the one that triggers first.
However, UK Consumer Protection legislation requires that plug-in domestic electrical goods must be provided with plugs to BS 1363, which include a fuse rated at not more than 13 A.
[10] Hence, all power strips sold in Australia and New Zealand with three or more 10A socket outlets are required to have overload protection so that if the total current drawn exceeds 10 A the inbuilt circuit breaker will operate and disconnect all connected devices.
On some power strips, the red, lighted rocker switch actually controls a thermal circuit breaker which flips to off when tripped.
This is especially likely if multiple high-power appliances are used, such as those with heating elements, like room heaters or electric frying pans.
When plugging a device into a power strip, a buildup of carbon or dust can cause sparking to occur.
A relocatable power tap is intended only for indoor use as a temporary extension of a grounding alternating-current branch circuit for general use.In Europe, plugs and sockets without additional control or surge protection circuits are outside the scope of the Low Voltage Directive 2006/95/EC and controlled by National regulations, and therefore must not be CE marked.
Examples of power strips exist in the U.S. patent system dating back as far as 1929, starting with the creation of Carl M. Peterson's "Table Tap".
