Cutout fuse type!!

Hi All,

Anyone know what type of fuses will be in a 200A cutout like the one pictured below?? I know they are 100A ones, but i need to know what type if possible so i can find suitable fuse that will discriminate with the cutout ones. At present the switchfuse protecting the submain has 200 amp fuses in it and then they wonder why the cutout fuses blew first..

View attachment 7893

Second question; See the earth terminal on the side of the cutout. How do i know if the DNO have linked it to the neutral and the supply is TNCS, or whether it is just a convenient place to fit a connection to the cable sheath, and the supply is TNS ???

Myself, i would have though a voltmeter between the earth terminal and neutral and see if there is a PD between the two...

john..

apprentice87 said:

See the earth terminal on the side of the cutout. How do i know if the DNO have linked it to the neutral and the supply is TNCS, or whether it is just a convenient place to fit a connection to the cable sheath, and the supply is TNS ???

Click to expand...

Enquiry.

apprentice87 said:

Myself, i would have though a voltmeter between the earth terminal and neutral and see if there is a PD between the two...

Click to expand...

It would be a good indicator of what it probably is.

iirc its an 88-2 type J

I don't think you can guess this one , as Lurchio says , make the enquiry , they're obliged to tell you.

That earth looks like it 's bolted to the cut-out  as if its TNS but its anyone's guess .

A loop test L-N and L-E should be identical if TN-C-S

As Steps said....loop,test

that cutout takes JPD style fuses....I have some in the garage :innocent

i can have a look at the type in morning if you want?

Hi all.

All it is is this.. Remember in my other thread the other day i was on about the factory where the cutout fuses blew twice in a row for no apparent reason. Well, i had a bit of a look on the weekend.. Did not get too involved, as it was so cold it was unbelievable, and i was not very well and could hardly think. It would have been dangerous for me to do much..

Anyway. i isolated both ends of the one submain, the one i suspected of having been damaged, and i did an IR test. It is a large cable, and i was too cold to wait around for a minute, [the required time] on each IR test for the reading to fully stabilise, but the following are not far out..

L1 - L2 = 30M

L1 - L3 = 70M

L2 - L3 = 70M

L1 - earth = 6M

L2 + L3 - earth = 70M [I think, was sooooo cold]

As for earth continuity, Zs at the board was more than good enough for the largest MCB in the board, a 63A "C" curve...

I was going to conpletely disconnect one end of the cable [to eliminate parallel earth paths] and do an R1 + R2 to try to evaluate the integrity of the armour, in other words, to calculate if the armour had any bits missing, but it was FAR too cold..

It is not possible to physically examine the cable for signs of damage, as most of it is high in the air and hidden behind steelwork..

Anyway, not a happy cable...

The DNO have told the owners that if the 100A cutout fuses blow again, they will refuse to replace them. The OCPD for the cable is 200A fuses [well clever..]

I have told the owners, that i can fit more suitable fuses in the switchfuse for them, [in case the fault reoccurs] thus hopefully avoiding the cutout fuses blowing, but that, owing to the cost of the cable [4 core 50 or 70 mm SWA] and the fact that you would need at least one, large boom type cherry picker to fit it, they need someone with a lot more experience than me to have a look at it..

They will leave it to see what happens..

john..

apprentice87 said:

Second question; See the earth terminal on the side of the cutout. How do i know if the DNO have linked it to the neutral and the supply is TNCS, or whether it is just a convenient place to fit a connection to the cable sheath, and the supply is TNS ???

Myself, i would have though a voltmeter between the earth terminal and neutral and see if there is a PD between the two...

john..

Click to expand...

There’s a removable link inside the service head between N→E. You have to hope the fairies will give you an insight to what’s in there.

Link fitted TN-C-S

No link TN-S

I did think of having a look, but they have just resealed it a few days ago. Fairies could be arranged, and it would sort out exactly what fuses were in the thing too. but playing with 200A cutouts is not really my thing!! I "think" i know what i am doing, but thinking and "knowing" are two different things!!!

I can ensure that the thing is "off load" if you like, while pulling fuses etc, but what if the fuse carrier falls apart when i am removing it of stuffing it back in..

john...

kerching said:

As Steps said....loop,test

that cutout takes JPD style fuses....I have some in the garage :innocent

i can have a look at the type in morning if you want?

Click to expand...

I think it is the "J" type fuses as you say, but if it blows again i will leave it to western power to supply and fit fuses i think. The "owners" of the cutout would be delighted if i announced that i could get more fuses and fit them if needed, but the problem is, if due to repeated overcurrents the service cable was damaged, they would be quick enough to blame me if the DNO had to dig half the street up to fix it..

[handy to know you have got some though!!!]

john..

J type fuses are easy enough to get hold of. But as you say, it’s only just been resealed and they’re not going to be happy with you.

apprentice87 said:

I did think of having a look, but they have just resealed it a few days ago. Fairies could be arranged, and it would sort out exactly what fuses were in the thing too. but playing with 200A cutouts is not really my thing!! I "think" i know what i am doing, but thinking and "knowing" are two different things!!!

I can ensure that the thing is "off load" if you like, while pulling fuses etc, but what if the fuse carrier falls apart when i am removing it of stuffing it back in..

john...

Click to expand...

*Insert lecture about playing around with DNO equipment here.*   

Hi Sweedy!! I quite agree!! You have got all leather and rubber stuff to wear [on your hands!!]

What size would the "fuse in the street" be?? [out of interest]

Another thing.. If you look at the two TP 100A cutouts on the left of the photo below, you can see that there is a green/yellow earth cable attached to them. This cable disappears under ground along with the service cable and presumably runs back to the cable sheath and the neutral in the service joint. Why would the DNO do that??

Also, why the TNCS supplies to a "multi occupancy" steel frame shed, thought that was not a good idea and the DNO did not allow it??

View attachment 7894

misssweden said:

*Insert lecture about playing around with DNO equipment here.*   

Click to expand...

can they refuse to replace the fuse? if they do then how are they supposed to get the power back on?

Andy™ said:

can they refuse to replace the fuse? if they do then how are they supposed to get the power back on?

Click to expand...

Just pick up a BS1202. simples! 

They can't refuse, but, they can charge, and they can delay until they get an acceptable EICR giving the install a clean bill of health.

If it went again after that, I think they would have grounds to withdraw a supply under ESQCR.

Sidewinder said:

They can't refuse, but, they can charge, and they can delay until they get an acceptable EICR giving the install a clean bill of health.

If it went again after that, I think they would have grounds to withdraw a supply under ESQCR.

Click to expand...

Yep, i would agree with that!! They apparently said that they would not fit any more fuses in case their service cable got damaged, and who could blame them.. I did tell the owners that the DNO would insist on an EICR before reconnecting them if it blew another one. It is obvious from the equipment installed that overloading is not the problem, but that fault current is.. I told the owners i will put 50A fuses in the switch fuse instead of the 200A ones, so at least next time the cutout fuses should survive. Surprised i cannot find any incinerated cables, accessories or pikeys though..

john..