flat sub mains- isolators

[J.C.E]

on my job i started today
a different contractor has done the mains (100a 3ph head>>100a 3ph iso>>63a ryefeild>> meters>>then into a 100a isolator switch (no fuse just a 100a main switch)

then I am responsible for the swa from here and then to consumer unit within the flats and the flat installs etc

should the isolator switch be fused- or is it ok to rely on the ryefeild fuse?

ta

 

[Pete999]

would imagine you are responsible for whatever you install, nothing more nothing less, I mean if you didn't install it how can it be you r responsibility?

 

[Toneyz]

If a 60/63A switch fuse is fitted there's not going to be much discrimination I don't think.

 

[J.C.E]

would imagine you are responsible for whatever you install, nothing more nothing less, I mean if you didn't install it how can it be you r responsibility?

not too concerned with the responsibilty- as the isolators are signed off by the previous contractor- but was thinking should the swa be fused down at the isolator or ok to just be at the ryefeild

 

[Toneyz]

As long as the cable is of the correct rating (taking in the correction factors for the installation methods) the 60/63A fuse should protect the cable.

 

[chris day]

The only issue i can see is you said Flats and not flat and one isolator.
if your supplying flats you would normally have multiple Ryefeild 63a ways>multiple meters>multiple isolators for each flat respectively.
If the cable size/installation method suits the 63a fuse then i cant see any issues, also if you made the final isolator a switch fuse then you would need to downgrade your capacity for discrimination between the two in line fuses.

 

[J.C.E]

The only issue i can see is you said Flats and not flat and one isolator.
if your supplying flats you would normally have multiple Ryefeild 63a ways>multiple meters>multiple isolators for each flat respectively.
If the cable size/installation method suits the 63a fuse then i cant see any issues, also if you made the final isolator a switch fuse then you would need to downgrade your capacity for discrimination between the two in line fuses.

is 6way r.b>6meters>5x iso (not one for l/l)

just in my head i had it should be fused for the swa rather than relying on r.b

so ideal world.....80a in r.b then 60a on isolator

 

[marc8]

on my job i started today
a different contractor has done the mains (100a 3ph head>>100a 3ph iso>>63a ryefeild>> meters>>then into a 100a isolator switch (no fuse just a 100a main switch)

then I am responsible for the swa from here and then to consumer unit within the flats and the flat installs etc

should the isolator switch be fused- or is it ok to rely on the ryefeild fuse?

ta

Hi J.C.E
quite lucky really you got an isolator after the Head before the Ryefield as it is only strongly advised by UKPN, a lot of companies fit the ryefield panel without the switch/ switch fuse. If the Ryefield is a 63amp unit & the correct fuse is fitted in the ryefield panel then it won't matter that there is a 100amp main switch as long as the cable to the flat is rated for the 63amps. The isolator after meter is there so if there is a problem the supply can be isolated from meter location.

 

[Cadgey123]

Does the DNO specify a Isolator before the RF panel?
I have usually wired Head>RF>Meter> Sw/Fuse to Con unit

 

[marc8]

Does the DNO specify a Isolator before the RF panel?
I have usually wired Head>RF>Meter> Sw/Fuse to Con unit

Hi Cadgey123
we are in the UKPN region & in their literature the wording is "strongly advised to fit a switch or switch fuse, also no recourse to pull the main fuses"

 

[J.C.E]

Hi Cadgey123
we are in the UKPN region & in their literature the wording is "strongly advised to fit a switch or switch fuse, also no recourse to pull the main fuses"

i see it as- they are usually pretty awkward anyway- so why give them anything to nibble on

 

[marc8]

i see it as- they are usually pretty awkward anyway- so why give them anything to nibble on

HI J.C.E
yes I understand that & also the fact if I allow in the price of the job around £400-£500 for a 200A switch fuse I might not get the job.
more worrying would be safe isolation & sending in one of my workers to work on the system that can only be partially be isolated from head to meter point at least with the SW/SWF can be safely isolated.
when installing a system locally for a few units Siemens engineer arrived to install fuses & mentioned if no isolator no fuses.

 

[TurboTim]

Solid link fuse carrier required prior to meter also to enable meter replacement!

 

[Taylortwocities]

Solid link fuse carrier required prior to meter also to enable meter replacement!

They pull the service fuse, change meter, and reseal.
Any switches etc always go after the meter.