MV cables with LV cables

[Sempronio1960]

I would like to ask if it is allowed lay MV cables (e.g. 20 kV) in tunnels or wells where LV power/control/monitoring cables are laid. See photos, please.

http://snag.gy/p1DsC.jpg

http://snag.gy/wswzq.jpg

http://snag.gy/Jb5o7.jpg

http://snag.gy/1iGwA.jpg

 

[7anoter4]

There are a few problems here:
1)the manhole, it seems to me, is very small-no room for cable pulling or cable joint if it will be necessary once, no ladder is provided and no grounding means.
2) the cables are not supported by cable trays.
3) for control cable no steel conduit or other separate enclosed magnetic raceways is provided in order to reduce the EMC.
4)medium voltage cables-it seems to be single core cables-all 3 phases have to run in a single duct.

 

[7anoter4]

1)correction:
instead of " in order to reduce the EMC" has to be " in order to reduce the EMI".
2)If the low voltage cables[power or lighting] are separated by a distance of 1 feet from the medium voltage cable it is permitted to be laid in the same room. However, NEC Art.392.10(L) requires a separation "by a solid fixed barrier of a material compatible with the cable tray."[no distance required].
3) If the medium voltage cable is labeled as "MC" it is permitted to be laid in the same cable tray with low voltage cables.
MC=metal clad cable- enclosed in an armor of interlocking metal tape, or a smooth or corrugated metallic sheath.[it seems to me it is not your case].

 

[Sempronio1960]

Thank you for answer. The Italian rules do not preclude the laying of cables MV cables together with LV cables.

 

[Padlock01]

Hi All, I agree with 7anoter4 manhole is too small however, in South Africa we size our manholes a metre sq and a metre deep for worse case MV cable depth
Seperate sleeve for MV, LV, Tel, and fibre optic cables, care should be taken on bending radius of MV and LV cables, one of the photos looks like a dogs dinner.
Padlock01

 

[dapotiti18]

From my practical experience,i will advise the control cable with the different control should be properly seperated.Also lv cable/control cable should be seperated from hv cable to prevent interference.
Dapo18

 

[fx007]

There is not even minimal separation between 20kV and the control cables. If anything happens, your control equipment will fry Look up at the codes, I think the separation requirement is minimum 4-6 diamaters of the largest cable. Also, I hope the parallel running is not very long, because your communication line will get inducted amps from the power cable.
Hope this help, and, BTW I would fire this contractor; poor work. I think everyone agrees ))