Ring main too big??

[Boaky]

I recently tested a doctors surgery and found a number of ring mains
are too large. r1 1.9 rn 1.9 r2 2.7. Zs 1.47 supplied from a type 2 32 amp breaker
could anyone suggest how best to rectify this.
Dont really want involved with the remedials but don't usually refuse work.
any of u guys any suggestions

 

[Farmelectrics]

its a poor shout saying the reqs are crap its what we try are best to work to im not trying to argue and as ive stated i would personally investigate why weve got a high zs reading if you measured the ring you could work out what the r1 r2 should be but failing all this and as a last resort for me i would install an rcbo and it would be acceptable under bs7671

 

[Farmelectrics]

no its not for just tt systems

 

[trev]

It's widely acknowledged that the regs are crap though mate
You have to admit they are really badly worded and open to interpretation

 

[GLENNSPARK]

its a poor shout saying the reqs are crap its what we try are best to work to im not trying to argue and as ive stated i would personally investigate why weve got a high zs reading if you measured the ring you could work out what the r1 r2 should be but failing all this and as a last resort for me i would install an rcbo and it would be acceptable under bs7671

now now...we`ll have no more of that...

no-one`s sayin the regs are crap....but theres certain aspects that need seeing to...

 

[GLENNSPARK]

It's widely acknowledged that the regs are crap though mate
You have to admit they are really badly worded and open to interpretation

theres a crackin example of it in the first few pages of the OSG Trev...

check out the pics of TT earthing arrangements...

a 16mm CSA main earthing conductor?...

 

[trev]

There's some utter nonsense in the OSG mate, we all know about the pic of the 25mm tails too don't we.
Hence "All tails MUST be 25mm!"

 

[GLENNSPARK]

There's some utter nonsense in the OSG mate, we all know about the pic of the 25mm tails too don't we.
Hence "All tails MUST be 25mm!"

yep...lol..

no thought given over to the I N of bullit...or Max. demand...with some diversity sprinkled in....

plastic innit....lol

 

[Knobhead]

Anyone seen the OP?

 

[Geordie Spark]

Anyone seen the OP?

Aye .. he's over ther in the corner cuddling a bottle of Jack Daniels with a bottle of Valium and a razor blade for company.

(but at least he's quiet and being "nice" )

 

[ash_s3]

Can it not be spit into two 20a radials?

 

[Knobhead]

Just when you thought it couldn't get any worse.

 

[ash_s3]

Just when you thought it couldn't get any worse.

Something I said?

 

[Hawkmoon]

Good grief!
Hang on a bit, isn't the 1667 only on TTs?

Yes that's what I understood - on 2391 course I remember B. Scaddan saying it only applies to TT (he also said technically it should be 1666 not 1667!) - though was about 6 years ago, has this reg changed?

 

[Engineer54]

theres a crackin example of it in the first few pages of the OSG Trev...

check out the pics of TT earthing arrangements...

a 16mm CSA main earthing conductor?...

That's because although they are falsely telling you an Ra of 200 ohms is a good-un on one hand, they are actually expecting you to achieve TN values of Ra on the other!! lol!!

 

[Engineer54]

There's some utter nonsense in the OSG mate, we all know about the pic of the 25mm tails too don't we.
Hence "All tails MUST be 25mm!"

That's because if 25mm tails are shown in a picture, then it MUST be correct, ...right??

What else would a 17 day/electrical trainee base sizing the tails on, all he knows is what's written in BS7671 and even more so, the pretty pictures in his OSG!! lol!!