Fusing SPDs in a Domestic Insrallation

[Pete999]

Question
Can anyone, direct me to the correct sizing and fusing of SPDs used on a Domestic installation? I asked the question at ELEX earlier today, but all I got was nonsensical techno babble from the Chap on the stand, to be honest I don't really think he knew what I was on about.
I ask because before the 18th the only experience I gad on SODs was in the Commercial environment, and I was using FURZ units grateful for any pointers.

 

[buzzlightyear]

o.a.p.,lol.their you go Pete a good night read with your coco enjoy

 

[Pete999]

o.a.p.,lol.their you go Pete a good night read with your coco enjoy .http://www.novaris.com.au/wp-content/uploads/2016/02/0015-D33V2-Surge-protection-installation-guide.pdf

cant see anything Buzz, more to the point cant open what you sent

 

[buzzlightyear]

redone it again for Mr Pete .

(edit by Dan: added PDF's to the actual post for you - In future, try to do that. )

 

[Pete999]

Thanks Buzz so very much, you avin a dig at me Mate Cocoa indeed? can't seem to find that in the wines section!!!!!! @ Tesco

 

[buzzlightyear]

you avin a dig at me Mate Cocoa indeed? can't seem to find that in the wines section

enjoy

 

[Deleted account]

Real debates on this one. Unsurprisingly.

Some manufacturers say they don’t need fusing down at all.

The Lewton say b32 in instructions instructions. I have seen others on B16

I asked 3 different manufacturers the same question got 3 different replies.

Hope that helped

 

[Midwest]

I'm still none the wiser. I know these things are now required by the 18th, with an exception, and what they are supposed to do; but how do they work and how are they wired in? Total ignorance and if someone could explain it to me, please.

 

[Deleted account]

SPD type 2 fitted inside cu

It has 3 terminations to it. Line neutral earth.

It is fitted next to other Mcb’s not on buz bar.

A brown 6mm conductor is terminated one end into the line terminal in the SPD, the othe4 end into a either a dedicated 32 amp Mcb or an mcb that is in use.*

A blue 6mm conductor is terminated between neutral bar in cu and N termination in SPD.

A green/ yellow 6mm conductor is terminated between met in cu and earth termination in SPD.

Easy

* some manufacturers like the SPD to have its own dedicated mcb. Others like it to share with and existing circuit, others don’t care and others don’t think an mcb is needed at all if it’s within the CU.


How they work. Electrickery or magic. These days known as science.

 

[Pete999]

Real debates on this one. Unsurprisingly.

Some manufacturers say they don’t need fusing down at all.

The Lewton say b32 in instructions instructions. I have seen others on B16

I asked 3 different manufacturers the same question got 3 different replies.

Hope that helped

Yes Thanks Pete

 

[Ian1981]

Basically upto 125 amps the cut out fuse I2t value will always be less than the K2S2 of the connecting conductors to the SPD from a csa of 4mm2.
So a typical spd has a metal oxide varistor with built in ocp and the fuse in the cut out will protect the connecting spd conductors.
Hager manufacturer their CU’s this way, some provide a separate ocpd such as a 32 amp mcb.

 

[Pete999]

View attachment 52382
Basically upto 125 amps the cut out fuse I2t value will always be less than the K2S2 of the connecting conductors to the SPD from a csa of 4mm2.
So a typical spd has a metal oxide varistor with built in ocp and the fuse in the cut out will protect the connecting spd conductors.
Hager manufacturer their CU’s this way, some provide a separate ocpd such as a 32 amp mcb.

Thanks Mate useful to know

 

[Ian1981]

It’s worth pointing out that the SPD is installed in parallel with the electrical installation and only requires short circuit/fault protection and not overload protection
Whether the DNO are happy with their fuse protecting the SPD conductors, well I’m sure they don’t care ha.

 

[Pete999]

It’s worth pointing out that the SPD is installed in parallel with the electrical installation and only requires short circuit/fault protection and not overload protection
Whether the DNO are happy with their fuse protecting the SPD conductors, well I’m sure they don’t care ha.

Yes I saw that method in a Demo this morning, hence my question, cuz Matey doing the demo didn't have a Scooby, came straight off the top of the M/S

 

[Ian1981]

I’d just go by the manufacturer Pete. If it comes pre fitted adjacent the main switch and not through a separate ocpd inside the CU then unless you believe it to be unsafe , then I’d be happy to just install as manufacturers say.