filling in forms please help asap

Peter Woodford · Aug 13, 2009

Guys,

Have done a few consumer unit replacements put can never remember all the areas to fill out can you remind me please.This is on the nic dom forms

1.single phase Prospective fault current (were does this come from) is this 16kA
2. Fuse type have a bs88 type RH do i but the RH under type
3. Particulars of install at the origin - Max demand (load) were do i get this from KVA/Amps
4. Have the following readings for a TN-S ze which reading do I but in the measured ze is it the 0.87 below
L-N 0.34 ohms - PFC 705A
L-PE 0.87 ohms - PFC 276A

how do i convert the pfc to kA

thanks I know i should know this by now but don't do enough installs at the mo not long started up and keep on forgetting the forms

zupos40 · Aug 13, 2009

Peter Woodford said:
Guys,

Have done a few consumer unit replacements put can never remember all the areas to fill out can you remind me please.This is on the nic dom forms

1.single phase Prospective fault current (were does this come from) is this 16kA
2. Fuse type have a bs88 type RH do i but the RH under type
3. Particulars of install at the origin - Max demand (load) were do i get this from KVA/Amps
4. Have the following readings for a TN-S ze which reading do I but in the measured ze is it the 0.87 below
L-N 0.34 ohms - PFC 705A
L-PE 0.87 ohms - PFC 276A

how do i convert the pfc to kA

thanks I know i should know this by now but don't do enough installs at the mo not long started up and keep on forgetting the forms

before you start recording result L-Pe PFC is Pefc (prospective earth fault current) and L-N PFC is Pscc(prospective short circuit current).

PFC is the highest value of either the Pefc or Pscc measured in your case it 705A or 705 divided by 1000 to convert it to Ka, thus 705A = 0.7 kA.

As for Maximum demand if property has central heating through out then you can put in down as 60A if not centrally heated then put 100A as max demand, (visit edf website and view page about applying for a new supply) for normal domestic installation there is little use trying to calculate Maximum demand as the tables in the OSG are 20 years out of date even the new table 17th edition O.S.G.

Ze = 0.87 ohms (which is a little high, O.S.G quotes Ze = 0.85 ohm)

lilygee · Aug 13, 2009

Peter Woodford said:
Guys,

Have done a few consumer unit replacements put can never remember all the areas to fill out can you remind me please.This is on the nic dom forms

1.single phase Prospective fault current (were does this come from) is this 16kA
2. Fuse type have a bs88 type RH do i but the RH under type
3. Particulars of install at the origin - Max demand (load) were do i get this from KVA/Amps
4. Have the following readings for a TN-S ze which reading do I but in the measured ze is it the 0.87 below
L-N 0.34 ohms - PFC 705A
L-PE 0.87 ohms - PFC 276A

how do i convert the pfc to kA

thanks I know i should know this by now but don't do enough installs at the mo not long started up and keep on forgetting the forms

1. This is the greater of your prospective short circuit current or prospective earth fault current.
2. Type bs88
3. Max demand at origin-the rating of your supply protective device, usually 100 amp, but may be lower
4.ze is always L-PE, in this case 0.87. Your pfe would be the higher value-705A