Technical Support
Sconet Nigeria Limited is geared towards the future with the vision to remain the preferred Electrical Facility Company in Nigeria.
Our approach to protection
With the goal to provide cost-effective facility protection, we follow the systematic protection plan which provides a comprehensive and highest level of protection.
This approach aims to:
- Capture direct lightning current with purposed designed air terminal.
- Conduct the lightning and surge energy safely to earth.
- Dissipate the energy effectively in the earth mass.
- Eliminate ground loops and potential differential.
In any environment for example, we endeavour to consider all necessary parameter, the structures, equipments and all interfaces to ensure that they are brought within the protection zone.
Frequently Asked Questions
No, as the electromagnetic effects and induction will still cause damage to equipment within the building. In actual fact, if you install external lightning protection, you will actually require lightning current arresters and surge arresters to be able to withstand the induced energy. Lightning strike can cause damage to sensitive electrical and electronic equipment located up to 1km away.
The lightning flash density in Lagos is about 6.9 strikes per km2. An average house within a built-up residential estate can therefore expect to be struck about once in 250 years. The same house can expect a surge to enter via the power cables at least 7 times a year. Thus power, television, telephone line protection are strongly recommended.
By installing surge arresters in your electrical distribution board, you are drastically reducing your risk of suffering damage via the power supply lines only, but not totally eliminating the risk.
Most likely. Surge arresters are only designed to withstand induced surges of up to a certain limit. A direct strike has far more energy which could destroy the surge arresters but they will still offer some protection. Due to the fact that your risk of a direct strike is so small you should worry more about the regular induced surges.
No, as they are designed to protect against high energy, high peak surges (transients) and not to operate as nominal voltage regulators.
No, it needs to be replaced.
The kA rating of the surge arresters has nothing to do with the fault current rating of electrical distribution board. You can fit a 40kA surge arrester in a domestic board with a fault current rating of less than 5kA. In larger panels with high fault current ratings, you must pre-fuse the surge arresters to co-ordinate and protect the surge arresters.
Not really. The surge arresters will not conduct evenly and thus installing 2 x 40kA surge arresters does not mean that the system can handle a surge of 80kA.
The (4/10) is actually half the energy of (8/20). A manufacturer’s claim of higher kA ratings in 4/10 is just a marketing gimmick. To overcome this problem all manufacturer must publish the surge handling capability at (10/350) for lightning current arresters and (8/20) for surge voltage arresters.
The Class 1 and Class 2 operate at different levels and have different energy handling capability. We recommend the installation of Class 1 in conjunction with Class 2 surge arresters to ensure complete protection.