surge protection devices

[ajdavies22]

Has anyone had any experience of installing surge protection devices?

I'm installing a 300A feed to a busbar chamber and then installing 3x3phase 12 way DB's above. What is the best way to incorporate the surge protection? I've been looking and it seems the only way to do it is for each of the DB's to have there own devices but obviously this is going to be very costly.

Any advice would be great!

 

[alanl]

Yes, for domestic installations.
It isnt going to be that expensive, I'd guess at £150 per DB.
Dehn are good for SPD, also these people:
Surge Protection Devices Ltd - protection of sensitive electronic equipment from damaging over-voltage surges including lightning
are very helpful,
You can probably fit it inside the DB, saving the cost of an external box.
Either of the 2 Companies above will be happy to help you if you give them a ring.

 

[Marvo]

What's your motivation for wanting to install surge protection?

 

[Knobhead]

Why do you need transient suppression on a 300A feeder?

Down stream protection is far better, the nearer the sensitive load the better. One disadvantage of high current transient suppression is, if it operates it is liable to destroy it’s self internally leaving the system unprotected for the next time. It will trip the breaker but you can just reset and leave the system unprotected.

So, what are you wanting to protect?

 

[Farmelectrics]

What's the reason for the spd

 

[ajdavies22]

The company I work for are building a special shipment mini warehouse under full temperature control for specialist and perishable cargo. Our customer has specified that they want the entire install protected by an SPD. It seems a bit of overkill to me as I don't believe that there's going to be a great deal that would or could get damaged. But as they say the customer is always right!

 

[Marvo]

With surge protection it's often a case of robbing Peter to pay Paul. In the event of a surge correctly specified SPD's will protect the load but may also cause tripping and power outage whilst doing so. Consequently if continuity of supply is equally or more important than protecting the machinery then SPD's may cause more problems than they solve.

Either way you'd be better seeking specialist advice for specifying SPD's. Navigating the numerous design considerations without the relevant experience is a recipe for disaster. Maybe approach one of the larger companies like Furse for assistance with the design.

 

[Knobhead]

But as they say the customer is always right!

Totally misinformed, but always right.

It’s their money!

I could understand it if there's delicate equipment, a mobile warehouse ? ? ? ?


I have fitted surge diverters many years back to my house out in the sticks on both the mains and telephone line. I built the units myself using transorbes (they didn’t cost me anything). They were wired in a delta formation.
Leg 1 live
Leg 2 neutral
Leg 3 earth

It stopped the answer phone, fax and computers blowing up every time there was a bit of thunder about (no internet then). At 1000ft elevation there were a few storms.

 

[westom]

Key to whether the protector does protection is how it connects to earth ground. That single point earth ground electrode must have a low impedance (ie 'less than 3 meter') connection to the protector.

Protectors work best when as low impedance as possible to earth. Increased separation between the protector and electronics also increases protection. BT, for example, wants their earthed protectors to be as much as 50 meters separated from switching electronics. Separation increases protection. But far more important is a connection to earth that is as short as possible (ie 'less than 3 meters' to the electrode), has no splices, is not inside metallic conduit, no sharp bends, and is separated from other non-grounding wires.

 

[topothehill54]

If its a small building then its right to fit the spd on the incomer, modern spd,d built to EN61643-11 will take many surges some are gauranteed 10 years, it will definately not trip the breaker as it only passes voltage to earth not current so your system will allways be protected.
The reason now for surge arresters is that todays electronic components are smaller ,faster and have more memory they are very sensitive to overvoltages, also companies and even domestic properties have many expensive electrical appliances each with its own micro processer which can get damaged,
If you want info and good prices i suggest Surge protection devices ltd they are very good.