Guest viewing limit reached
  • You have reached the maximum number of guest views allowed
  • Please register below to remove this limitation

telectrix

-
Mentor
Arms
hi folks, got a CU change to do. flat rewired circa '70's. wylex 3036 fuses.

my concern is earthing conductors. at present they are 6.0mm. TN-S.

Pefc is 700A. not sure of main fuse size, so have taken worst scenario at 100A.
referring to tables, @ 700A the disconnect time for a 100A BS1361 is 2 secs. so the adiabatic gives a S of 6.91 for the MEC.

thoughts. please.
 
tails from isolator to flat CU are 10mm. can only check DNO fuses if the seal fairy comes.

and there's no sign of damage over last 30 odd years. flat is minimal load. 1 cooker cct. 1 socket cct, 2 lighting. shower is off boiler which is communal. total load is probably < 20A.average.
 
Last edited:
if the fuse is 60A, then the adiabatic gives a MEC size of 2.19mm.so well in with 6.0mm. as you say, murdoch, common sense prevails.
 
Gosh Tel... I think in this case I'd be very, very tempted to employ the seal fairies. It sounds like a lot of upheaval for the customer based on the assumption that it's a 100A fuse.
 
even at 100A for the fuse.the 6.0mm is borderline, so i'm going to go ahead and leave it with an observation on the EIC.
 
The fuse is almost bound to fall out when you do the cu change, why not make sure it is only a 60A?
I never seek authorisation to reduce a fuse rating, only to increase it.
As a matter of course my DNO replaces 100A fuses with 80s whenever they come accross them, often the meters are only rated at 80A anyway.
 
Sometimes it seems the seal fairy has changed the DNO fuse ....
I bet you thought twice before writing that Murdoch:D
I wish there was a 'brave/risky/but we all agree' button!
 
Best EV Chargers by Electrical2Go! The official electric vehicle charger supplier.

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

Advert

YOUR Unread Posts

Daily, weekly or monthly email

Thread starter

telectrix

Mentor
Arms
-
Joined
Location
cheshire/staffordshire
If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
United Kingdom
What type of forum member are you?
Electrical Engineer (Qualified)
Business Name
Telectrix

Thread Information

Title
calculation check before i rip the flat to bits.
Prefix
N/A
Forum
Electrical Wiring, Theories and Regulations
Start date
Last reply date
Replies
23

Advert

Thread statistics

Created
telectrix,
Last reply from
stevels4,
Replies
23
Views
2,360

Advert

Back
Top