Every homeowner should make sure that their homes have adequate surge protection, so you should ask your electrician about surge protectors if your house lacks sufficient surge protection equipment.
Having a surge protector allows you to plug several appliances and devices into one power outlet without creating an electrical hazard.
What Is a Power Surge?
A power surge, or a transient voltage, occurs if the voltage increases drastically above an appropriate level, which is usually 240 volts for homes in the United Kingdom.
Voltage measures a difference in electric potential energy as an electric current flows from one end of a wire to the other end.
Your electrician may talk to you about “spikes” and “surges.”
A spike occurs if the voltage increases for less than three nanoseconds, and a surge occurs if the voltage increases for at least three nanoseconds.
Lighting strikes, downed power lines, faulty wiring, the use of high-power appliances and electrical devices, and problems with your utility company’s equipment can cause power surges.
Why Does Your Home Need Surge Protection?
Surge protection prevents damage to electronic devices by blocking power surges.
Surges can burn wires and destroy your devices and appliances, or at least decrease their longevity.
Surge protectors prevent this damage by redirecting the excess electricity to a grounding wire.
People who work from home or any business could lose valuable and irretrievable data.
Even with the assurance of back up devices, customers could be in the delicate position of losing information which could cost them greatly.
Protection can be given to help prevent such damage through the inclusion of ‘Surge Protection Devices (SPD). This protection isn’t always mandatory but they’re becoming more of the norm to help protect valuable data and equipment.
Homeowners often purchase surge protectors like gas discharge arrestors and metal oxide varistors (MOVs).
Gas discharge arrestors are gas tubes that utilise inert gas a conductor between the hot line and the ground line to redirect the electricity.
MOVs activate when excess voltage occurs, and they divert the surge without blocking the standard current to power devices and appliances.
Your electrician will probably recommend a surge protector with a response time of less than one nanosecond because surge protectors have slight delays before they divert a surge.
Short response times provide the best protection against power surges.
So do you need to consider surge protection?
Here’s five things you need to know:*
- A bolt of lightning
One of the threats to devices is lighting.
A discharge from lightning near a power supply cable could generate a significant over-voltage transient and cause damage.
Even power cables underground can be affected, with a nearby lightning strike causing the over-voltage to be induced.
Transient over-voltages transmitted by the supply distribution system are not significantly attenuated downstream in most installations This over-voltage transient could then travel down the power lines and arrive at the installation, causing damage to the equipment within.
In most cases, surge protection devices aren’t required for installations to protect the equipment in the event of a lighting strike. However, protection may be necessary in applications where higher reliability or higher risks (e.g. fire) are expected.
Surge protection devices are classified according to their standard into different types. There are three types of surge protection device:
- Type 1 – This can discharge partial lighting current and commonly employs spark gap technology
- Type 2 – This version can help prevent the spread of over-voltages in electrical installations and help protect connected equipment
- Type 3 – These are only required to be installed as a supplement to Type 2 and have a low discharge capacity.
When installing these devices, a Type 1 or Type 2 devices may be used at the origin whilst Type 2 or Type 3 are also suited for locations close to the protected equipment to further protect against switching transients generated within the building.
When installing a surge protection device, you should refer to BS 7671 for the correct regulations.
- Getting the right connection
Making sure a connection is correct is vital when using surge protection devices. To obtain the maximum protection from the SPD, the connecting conductors should be kept as short as possible. This is to minimise any additive voltages on the connecting cables.
The connecting conductors of a Type 1 SPD shall have a cross sectional area of not less than 16mm² and for Type 2 the conductor size should be not less than 4mm² copper where the line conductor is this or greater.The total connecting lead length (a+b) due to these devices usually being connected in paraller with the supply should preferably not exceed 0.5m but shall in no case exceed 1m.
If there is a distance greater than 10m between the SPD and the sensitive equipment to be protected, oscillations could lead to higher voltage values appearing at the equipment terminals. In this case, additional coordinated surge protection devices close to the equipment should be considered.
A residual current device monitors your wiring installation permanently to detect any leaking current. How? It continuously measures the amount of current passing through a wire in one direction, and again through a different wire in the opposite direction.
- If it detects a difference greater than 300 mA (milliamps), or less in certain cases, it breaks the circuit.
- If current is “missing”, it means there is a leak somewhere in the wiring installation. If this current leaks through a person’s body, it could lead to a potentially fatal electrocution.
Residual current devices protect people.
Should RCD’s be required in your installation for example in TT systems, the SPD should be installed upstream of this RCD. If this can’t be avoided, the RCD should be time-delayed or be an S-type.
- Inspection & Testing
Surge protection devices can offer a visual indication to help with the inspection and testing process.
Usually colour coded, if a green light is displayed then this means the device is operational.
If a red light is displayed however, it means that the device has reached its end and needs replacing.
In some cases the SPD will have replaceable cartridges that can be simply plugged in.