Surge protection

Billi 12

I'm looking to install some 3 phase type 2 spd units to sub panels, I know the wiring regulations have recently changed and am unsure.
Is the 0.5m rule still relevant?
Can I connect to the load side of an existing mcb?
Can I connect directly from the load side of the main isolator?

Thanks for the help

Hmob

Billi 12 wrote: »

I'm looking to install some 3 phase type 2 spd units to sub panels, I know the wiring regulations have recently changed and am unsure.
Is the 0.5m rule still relevant?
Can I connect to the load side of an existing mcb?
Can I connect directly from the load side of the main isolator?

Thanks for the help

I'll take a stab at it, don't have copy of ET 10101 yet

1.. yes I believe

2.. no ,fitted next to isolator ,wired after isolator and protective device for spd

3. I'm guessing on this but for discrimination purposes and protection of board and spd ,I would say the spds are protected in the board they're fitted not upstream
Data sheet will probably say?

Billi 12

Hmob wrote: »

I'll take a stab at it, don't have copy of ET 10101 yet

1.. yes I believe

2.. no ,after isolator and protective device for spd

3. I'm guessing on this but for discrimination purposes and protection of board and spd ,I would say the spds are protected in the board they're fitted not upstream
Data sheet will probably say?

Thanks Hmob I thought that I could fit an individual mcb or use an existing one to feed the spd.

Hmob

Billi 12 wrote: »

Thanks Hmob I thought that I could fit an individual mcb or use an existing one to feed the spd.

Afaik protective device and spd goes next to isolator

50cm is total length of cabling from isolator thru pd and spd to earth terminal

No sure is the 50cm is a regulation

Billi 12

Hmob wrote: »

Afaik protective device and spd goes next to isolator

50cm is total length of cabling from isolator thru pd and spd to earth terminal

No sure is the 50cm is a regulation

I think there's an allowance on cabling not to exceed 1m.
Main isolator to feed a pd which in turn feeds the spd which runs to earth?

Risteard81

Some SPDs require their own protective device, whereas others will declare that they are adequately protected by the main overcurrent device. Really you'll need to look at the documentation for the specific SPD you're using.

Hmob

Billi 12 wrote: »

I think there's an allowance on cabling not to exceed 1m.
Main isolator to feed a pd which in turn feeds the spd which runs to earth?

Ya I seen that

0.5 m recommended ,max 1m
Not sure if there's anything in ET101

Refreshed my memory on it there

You must have protection at the main board always

Type 1 is needed if u have lightning protection

Type 2 otherwise

Type 3 protects electrical equipment?

Hmob

Risteard81 wrote: »

Some SPDs require their own protective device, whereas others will declare that they are adequately protected by the main overcurrent device. Really you'll need to look at the documentation for the specific SPD you're using.

If there is a protective device for the board

A lot of sub boards only have an isolator, I was assuming no main protection in board

Agree on checking documentation

Risteard81

Hmob wrote: »

A lot of sub boards only have an isolator

There will still be an upstream protective device (or certainly should be).

Billi 12

Risteard81 wrote: »

Some SPDs require their own protective device, whereas others will declare that they are adequately protected by the main overcurrent device. Really you'll need to look at the documentation for the specific SPD you're using.

No mention of a separate protective device needed, just says "must be installed on the load side of the main overcurrent protection"

Risteard81

Billi 12 wrote: »

No mention of a separate protective device needed, just says "must be installed on the load side of the main overcurrent protection"

So then the main overcurrent device must be sufficient for it.

Billi 12

Hmob wrote: »

If there is a protective device for the board

A lot of sub boards only have an isolator, I was assuming no main protection in board

Agree on checking documentation

Just a 100a main isolator feeding the board

Hmob

Risteard81 wrote: »

There will still be an upstream protective device (or certainly should be).

Sorry yes there will obviously upstream

I was trying to get the terminology right for the isolator/protective dervices at the sub board( I still can't remember)

Im used to devices called main devices being at the main board

Billi 12

Risteard81 wrote: »

So then the main overcurrent device must be sufficient for it.

Appreciate your help

Hmob

Billi 12 wrote: »

Just a 100a main isolator feeding the board

I get the point about the protective device for the sub board protecting the spd, I figured that would be the case for some

Not fully convinced on spd protection being upstream of the sub board, could be wrong though