Surge Protection with Varistors / Gas Discharge Tubes

[Subbu68]

Recently, one FM had raised a point on getting a power strip with surge protection.

I do not face any serious power issues in Abu Dhabi where I live. Rather the supply is very stable and being entirely on underground cables, lightning surges are not easy to get in. The only place for lightning to enter is the 400kV overhead lines but with 400kV > 132kV > 11kV > 400V (230V 1ph)- surge arrestors, cables and transformers would damp out such surges.

Out of curiosity started reading on applying Varistors and Gas Discharge Tubes to protect the audio / video equipment, ultimately to add these devices to the existing power strip.

From the specs of Varistors, choosing a maximum voltage of 275V yields and clamping voltage of 700V or so. A bit concerned if this could still fry the step down transformers in the Audio equipment. If clamping voltage is chosen low like 300V, the maximum Vrms drops down to 130V or so that at nominal voltage of 230V itself it would breakdown.

Has anyone done any research or has experience building a power strip with Varistors / GDTs to protect his A/V equipment?

 

[sdk]

Why not use SPDs at your main box?

 

[Subbu68]

Why not use SPDs at your main box?

The solution was the best but most of the expats here live in rented house. We cannot modify anything on the main installation. At the most run an extension or change the lights to what we want.

 

[grindstone]

I don't know if their offerings work for your power, but I just discovered an outfit called zerosurge that seems to take a different approach. From what I'm seeing, it's like a sort of automatic gain control in cascade that diverts. Still reading about their ideas, but, with your skills, I'd think you could adapt basic ideas for series attenuation. But diy with gas tubes would be WAY more fun