Testing street lighting columns

[Lighting]

Hi all i have some work coming up testing street lighting columns on price per columns so i want to get myself ready, I've done street lighting work before but all the testing I've seen done was never done right This is what they are looking for

Polarity
Continuity of Protective Conductor
Insulation Resistance
Prospective Short Circuit Current (PSCC)
Earth Electrode
RDC Tests[FONT=Verdana, Arial, sans-serif] [/FONT]
[FONT=Verdana, Arial, sans-serif]But i they have told be that its only testing at the base of the column and that we are not disconnecting the control gear in the lantern but pulling the DNO fuse at the base.[/FONT]

[FONT=Verdana, Arial, sans-serif]so this says to me that we are only checking the supply Ze and the main earthing.

Any thoughts, tip would be a great help

Thanks ​ [/FONT]

 

[Engineer54]

I doubt very much if the fuses in these street lighting columns are the DNO's, ...lol!!

So what else did you want to test at these columns then, the lamp ballasts?? You can do L-N to E tests on the cable upto the Ballasts...

They are asking you to provide test reports on these lighting columns distribution circuits, and that's all contained at the bases of these lighting columns. Why you would want to test upto the lamps themselves i don't know??

 

[Lighting]

Hi Engineer54 most of the columns have a DNO supply so i will have to pull the DNO fuse to isolate the circuit that go's the the ballasts / lamp to get the Ze
if i don't disconnect the lamp/ballast i can not do IR or R1 + R2
To do L-N to E tests on the cable upto the Ballast wont i have to remove the lamp to get a true reading?

 

[Richard Burns]

If you are testing the distribution circuits then you do not need to test anything past the supply fuse.
If you are testing the wiring in the column itself then as E54 says you can do a connected L+N to E IR test.
If the column has metal work; is this in connection with the CPC, if so, OK.
Polarity, Prospective Short Circuit Current (PSCC), Earth Electrode can all be done for the dist circuit.

 

[Engineer54]

Hi Engineer54 most of the columns have a DNO supply so i will have to pull the DNO fuse to isolate the circuit that go's the the ballasts / lamp to get the Ze
if i don't disconnect the lamp/ballast i can not do IR or R1 + R2
To do L-N to E tests on the cable upto the Ballast wont i have to remove the lamp to get a true reading?

Why would all the street lighting columns have a DNO fuse in them?? That just seems illogical to me, where are they supplied from??

I can perhaps accept there be a single DNO fuse at the street lighting distribution cabinet, or even at the first post in a string of posts, but not at every post!!

 

[richardsolway]

Some columbs do have DNO fuses.......normally the first on the supply run or supply cabinet.(I work for SSE), have changed columbs with these in too.....now thats a fun experiance! all others have isolators (Mcb + M/sw) or street furniture cutouts. Have seen metal clad spurs too.......It really depends on age.

Polarity - speaks for its self
Continuity of Protective Conductor - between main earth and columb......also feed cable to head if applicable
Insulation Resistance - load cables and columb
Prospective Short Circuit Current (PSCC)- at cutout
Earth Electrode - rarely
RDC Tests - huh! very rare!!!!!!

Now i have not worked on that side for 10 years.... but thats about all that you can do with testing given your spec.

 

[Lighting]

Hi i have work on many columns, sign post that have had DNO supply in them and not just in the first column but all down the street.
It is sometimes cheaper for the local council.
If the DNO has a main running down the road it cheaper to use that than digging up the road to lay there own swa and if there is ever a fault on it they can pass it back to the dno instead of have to deal with it them self


Do i do a soft IR (250v) test so i don't damage the control gear