Departurtes

[duncanhead]

You won't find an RCD protecting the DNO service cable though.
You'll get the full 560A if the cable faults, how the cable behaves is another matter.

I'd think that you'll be surprised, the DNO feeds are very good - so is thier protection, as I said I wouldn't want to try it in practice, 2 reasons, it'll take the whole block out, and the DNO may then want to replace thier feed to my system board, (would require digging up 2 rooms and a nice driveway)...

.. and to create this sort of fault is (death), I know it as I've heard from a colleague that some one dropped a spanner ( but don't site me) and "melt down" occured, the person died a week later.... not a "nice" "picture"...

 

[jockspark]

ah ha i have it sussed this thread will come to a close next sunday
if my calculations are correct

 

[RF Lighting]

How is a 560A BS88 fuse good protection for a 16mm service cable?

 

[duncanhead]

ah ha i have it sussed this thread will come to a close next sunday
if my calculations are correct

why Sunday?

 

[Markey]

march fools day they moved it a month early just for this occasion

 

[ricicle]

Mods - please lock this thread, it is going nowhere.

 

[duncanhead]

ah ha i have it sussed this thread will come to a close next sunday
if my calculations are correct

why Sunday?

Ok !!!!

 

[duncanhead]

march fools day they moved it a month early just for this occasion

yea - sussed that - it took me 15 ms, just a bit quicker than my WYLEX RCBO ...!!!

 

[Spark123]

You won't find an RCD protecting the DNO service cable though.
You'll get the full 560A if the cable faults, how the cable behaves is another matter.

I'd think that you'll be surprised, the DNO feeds are very good - so is thier protection, as I said I wouldn't want to try it in practice, 2 reasons, it'll take the whole block out, and the DNO may then want to replace thier feed to my system board, (would require digging up 2 rooms and a nice driveway)...

Not that good though, I don't know what they use in the box in the street but I'd imagine some sort of BS88 fuselink. I have never come across a DNO supply cable which has upstream RCD protection.

.. and to create this sort of fault is (death), I know it as I've heard from a colleague that some one dropped a spanner ( but don't site me) and "melt down" occured, the person died a week later.... not a "nice" "picture"...

I have seen the video too about the computer place that wouldn't let them turn off the supply.

 

[jockspark]

march fools day they moved it a month early just for this occasion

yea - sussed that - it took me 15 ms, just a bit quicker than my WYLEX RCBO ...!!!

well you have got everything else wrong why not the month
is this a wind up ? please tell me it is

 

[duncanhead]

How is a 560A BS88 fuse good protection for a 16mm service cable?

hmmm.. it'll actually be a 100 Amp fuse, need to check out the specs for the DNO fuses and what mm2 thier supply actually is, (I'm not going to try and measure it (each core) with my micrometer though) but as you rightly know fuses "run" at overcurrent" for quite a few seconds if not an hour (depending on the over current) as relating to the "nominal" rating.... Why do you think that I wouldn't what to "upgrade" to a 100 Amp fuse if I knew that 80-100Amps+ were regularly loaded thru it ( the original 60 Amp fuse)?

 

[Spark123]

The 100A fuse in the service head (or whatever size it is) does not protect the DNO cable entering your property, this is protected by the next DNO fuse upstream wether it be a 315A fuse I don't know. Only they can answer that.

 

[duncanhead]

You won't find an RCD protecting the DNO service cable though.
You'll get the full 560A if the cable faults, how the cable behaves is another matter.

I'd think that you'll be surprised, the DNO feeds are very good - so is thier protection, as I said I wouldn't want to try it in practice, 2 reasons, it'll take the whole block out, and the DNO may then want to replace thier feed to my system board, (would require digging up 2 rooms and a nice driveway)...

Not that good though, I don't know what they use in the box in the street but I'd imagine some sort of BS88 fuselink. I have never come across a DNO supply cable which has upstream RCD protection.

.. and to create this sort of fault is (death), I know it as I've heard from a colleague that some one dropped a spanner ( but don't site me) and "melt down" occured, the person died a week later.... not a "nice" "picture"...

I have seen the video too about the computer place that wouldn't let them turn off the supply.

I don't believe it's RCD type protection, I can find out exactly how/what the "protection" is, but this would take me about a week and I might not be able to publickly disclose my "findings"

 

[XtraRaptor]

You won't find an RCD protecting the DNO service cable though.
You'll get the full 560A if the cable faults, how the cable behaves is another matter.

I'd think that you'll be surprised, the DNO feeds are very good - so is thier protection, as I said I wouldn't want to try it in practice, 2 reasons, it'll take the whole block out, and the DNO may then want to replace thier feed to my system board, (would require digging up 2 rooms and a nice driveway)...

.. and to create this sort of fault is (death), I know it as I've heard from a colleague that some one dropped a spanner ( but don't site me) and "melt down" occured, the person died a week later.... not a "nice" "picture"...

hmmm.. it'll actually be a 100 Amp fuse, need to check out the specs for the DNO fuses and what mm2 thier supply actually is, (I'm not going to try and measure it (each core) with my micrometer though) but as you rightly know fuses "run" at overcurrent" for quite a few seconds if not an hour (depending on the over current) as relating to the "nominal" rating.... Why do you think that I wouldn't what to "upgrade" to a 100 Amp fuse if I knew that 80-100Amps+ were regularly loaded thru it ( the original 60 Amp fuse)?




If the supply is for the block I don't think it will be 100A



Can't wait for Sunday...

 

[duncanhead]

The 100A fuse in the service head (or whatever size it is) does not protect the DNO cable entering your property, this is protected by the next DNO fuse upstream wether it be a 315A fuse I don't know. Only they can answer that.

yea, see my later posting..