Zs

[Plonker 3]

I'm good, many fingers in many of pies at the moment. I might be going into the LV Live cable jointing side of things! Any one know what the fault current is on a sub station main fuse across 2 phases whilst standing in a trench with 2ft of water in it? LOL, hope I get that job, its looking promising msl:

Sod that, seen them doing it before, either brain dead or balls of steel to do that.

 

[Badged01]

anyway, the question is irrelevant. BS7671 and hence the efli's in there only apply to the customer's installation. they do not apply to DNO supplies.

Congrats Tel, I guess you've been promoted onto the moderator staff and are stopping the fun ... :smiley2:

 

[Silly Sausage]

Then comes along DW Cockburn to spoil the fun!

He's so obviously mental though!
I've got a copy of one his works of art on the computer somewhere.
Let me know if you want it.

 

[Paul.M]

I do my best and its nice to be appreciated, i also learn a lot from others on here as well, and not all the people i learn from have my experience, and this backs up the things i say from time to time, there are no stupid questions, only questions you don't know the answers to.

Cheers……………Howard

Howard I agree with that 100%. You are a top bloke. I was at Jay's house last night talking about you, all good btw

Thanks for helping/confirming my calcs on that 3 phase sub board back end of last year. Yes, we were correct (tell you later).

I'm thinking of going down the same route as Jay and Phil next year, may need your help on that score? Lets talk about it over a round of golf, my treat

 

[Paul.M]

Sod that, seen them doing it before, either brain dead or balls of steel to do that.

I'm a bit of both, hope I get the job! :rofl:

Look, after working with/for some of the caricatures off this forum, this will be easy LOL.

 

[HandySparks]

...or balls of steel to do that.

Think a pair of insulated ones would be preferable. :biggrin:

 

[Paul.M]

Think a pair of insulated ones would be preferable. :biggrin:

I like that one . Instead of 4KV gloves I will wear 4KV Y-fronts. Lets see what happens in the next few months???

 

[Plonker 3]

I don't want to se you in a pair of Y fronts with your steel balls thank you.

 

[Zebra Stripe]

Brain dead at the mo,a 100 amp bs1361 fuse max Zs is .030,so how come tncs supply allows max 0.35 & tns supply allows max .80,surely the main fuse must comply to max allowed Zs in bs7671,any thoughts cheers

Hey Cliffed BS1361 fuse @ 100amps has a max Zs of 0.36ohms for 5 seconds disconnection (0.29ohms using RoT)

I think the confussion comes from the fact that a TNC-S system has max Ze of 0.35ohms and as such how can it(BS1361) comply with a max Ze if the RoT is applied - ie 0.29ohms maximum and max Ze of 0.35ohms for TNCS and even without the RoT for a TNS system at max Ze of 0.8ohms...
The answer I believe has already been given, ie if the BS1361 is the main fuse it is out of the scope of BS7671 and its max Zs values come under ESQC Regs as its DNOs equipment with different criteria. If protecting sub-main cable though it would need to comply though.
Good question and cant see why its been ridiculed.

 

[Plonker 3]

I haven't seen anyone ridiculing the question.

 

[Zebra Stripe]

You may want to read the thread with fresh eyes then, cos thats what it comes across like.

 

[Plonker 3]

I think his terminology and attitude when asked to look up something himself have been ridiculed, but the original question hasn't.

 

[cliffed]

Thxs for your explanation,maybe I didn't explain it fully & correctly but it's great to have it answered,& I also thought it was a good question cheers

 

[Badged01]

Thxs for your explanation,maybe I didn't explain it fully & correctly but it's great to have it answered,& I also thought it was a good question cheers

Hanging in there, take a little bit of banter and niggling, shake it off and the answer(s) will come! Us crusties have gotta have some fun along the way .....

 

[Hawkmoon]

Agree with Zebra on this

The guy had already looked up the info before discussing it on here...not really the typical lazy assed questioner we sometimes get is he? -

I'm guessing there are a number of members (all levels of exp) put off posting to this forum as they are tired of the all too often belligerent and unnecessary slating that goes on.

I know we experience a fair amount of banter on site (particularly multitrade) but that's usually of humorous intent.

 

[Deleted member 26818]

Bit confused, not too sure what the question was?
It seems to be something about the max Zs for the OCPD being higher than that for the installation?
Can't actually see a problem with that myself?