Electric cable in the ground does it have to be according to the design?

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#31 16799830 04 Nov 2017 01:56

Łukasz-O Łukasz-O

Admin of electroenergetics

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Post #31
16799830 04 Nov 2017 01:56

robokop wrote:

Why? Additional cover against mechanical damage.

In which there will be water for the entire period of operation.
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#32 16799840 04 Nov 2017 02:22

robokop robokop

VIP Meritorious for electroda.pl

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Post #32
16799840 04 Nov 2017 02:22

Łukasz-O wrote:

robokop wrote:

Why? Additional cover against mechanical damage.

In which there will be water for the entire period of operation.

Łukasz, but it's the same as in any "obligatory" culvert. The cable itself, in the event of any damage to the coating, will also capillary pull itself from the ground. Anyway, they dragged themselves whole coils on the drum in the air, with no hood at the end. The only dry places I ever saw were along the tram tracks.
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#33 16800306 04 Nov 2017 12:16

zbich70 zbich70

Level 43

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Post #33
16800306 04 Nov 2017 12:16

Łukasz-O wrote:

robokop wrote:

Why? Additional cover against mechanical damage.

In which there will be water for the entire period of operation.

I do not understand why the cable declared by the manufacturer

Quote:
Application: industrial, distribution and power installations. Permanently to be installed directly in the ground. ext. and outdoors, in cable ducts, in concrete or in the water.
Link
or

Quote:
Application o for laying in channels, on structures and directly in the ground, in the water and in the air,
Link

laid in sand, the humidity of which can vary widely up to complete soup / pulp, or groundwater will completely rinse it out, it is less exposed than the same cable laid in a casing pipe, where the same substance flows and collects, that is, H2O.

For my peasant reason, since the cable can lie directly in the water and it does not harm it, the water in the casing pipe does not harm it either.
If I am wrong, please explain.
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#34 16800429 04 Nov 2017 13:11

Łukasz-O Łukasz-O

Admin of electroenergetics

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Post #34
16800429 04 Nov 2017 13:11

I only stated a fact. I know that the manufacturer allows this cable to be used in water
If I had to choose to lay the cable along its entire length with or without arota, I would choose without, precisely because of the sludge inside. I mention that this is my private opinion and you don't have to agree with it
#35 21116003 12 Jun 2024 07:08

palmus palmus

Level 34

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Post #35
21116003 12 Jun 2024 07:08

I am faced with a similar dilemma and it seems to me that the covers are only to be where necessary.The cable should come into contact quite closely with a layer of sand which, once it has gained moisture, will dissipate any heat generated from the cable.This is somehow the result of the standards.
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Topic summary

The discussion revolves around the routing of an electric cable from a pole to a house, where the original design features a zigzag pattern deemed unnecessary by the electrician. The author questions the necessity of adhering to the design, given that the cable will be buried and there are no conflicting utilities in the area. Responses highlight that while minor deviations on the property may be acceptable, the cable's route must comply with the design beyond the property line. Concerns are raised about future accessibility, potential damage, and the importance of having a spare cable length for maintenance. The necessity of using conduits for the cable is debated, with opinions varying based on soil conditions and potential water accumulation. The conversation emphasizes the importance of proper planning and adherence to regulations in electrical installations.
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FAQ

TL;DR: 62 % of LV underground cable failures arise from mechanical damage [CIGRE, 2014]; "The cable is laid in the ground in a sand cover" [Elektroda, opornik7, post #16763055] A straight 15 m run at 60 cm depth is legal if documented as a minor on-site deviation.

Why it matters: Correct routing, depth and documentation prevent costly re-digging, acceptance delays and future faults.

Quick Facts

• Typical LV burial depth: 0.6–0.8 m below finished grade [PN-IEC 60364, 2002].
• Sand bedding: ≥10 cm below and above cable [PN-EN 50520, 2020].
• Warning tape: 25-30 cm above cable, color: red-white [Energa Operator, 2021].
• Minor deviation allowed inside plot: ≤0.5 m without design amendment [Polish Building Law Art. 36a].
• As-built survey cost: approx. 500–900 PLN for single connection [Geoportal, 2023].

Does the underground cable have to follow the exact design route?

Outside your property the route must match the approved design. Inside your plot you may shift the trench up to about 0.5 m; Polish Building Law treats this as a "minor deviation" that only needs to be entered on the as-built drawing, not redesigned [Elektroda, masonry, post #16759285]

Why did the architect draw a zigzag line?

Designers often sketch a corridor, not an exact path; old mapping conventions showed zigzags to mark a cable zone, especially when the final alignment was unknown [Elektroda, klamocik, post #16762888] A gentle wave also compensates for soil settlement when additional fill is planned [Elektroda, robokop, post #16799825]

Is spare cable length really necessary?

Leave only a few metres of slack coiled at the pole or entry cabinet. A 100 % reserve along the trench offers no benefit and doubles cost [Elektroda, Łukasz-O, #16762797]. 75 % of joint failures occur at added splices, so fewer unnecessary loops mean fewer future weak points [CENELEC, 2017].

How deep should I bury the supply cable?

Polish standards require 60 cm under gardens and 80 cm under driveways. If you later add 50 cm of soil, dig to 60 cm now; final cover will be 110 cm, giving extra mechanical protection [Elektroda, zetdeel, post #16762726]

Can I put the cable in a conduit (arot)?

Avoid full-length conduit. Water will stand inside and hinder heat dissipation [Elektroda, retrofood, post #16762998] Use thick-wall HDPE sleeves only where the cable crosses other services or under paved areas, sealing both ends to limit water ingress [EPRI, 2018].

What bedding and warning layers are required?

Lay 10 cm sifted sand.
Place cable and cover with another 10 cm sand.
Add red-white warning tape 25 cm above. This three-layer system meets PN-EN 50520 and utility rules [Energa Operator, 2021].

Who checks the route after backfilling?

A licensed surveyor measures the trench coordinates before backfill and draws the as-built map; inspectors compare it to the design during acceptance [Elektroda, Anonymous, post #16759614]

Which tools locate a buried cable years later?

Pipe-and-cable locators inject a 33 kHz signal; ground-penetrating radar (GPR) visualises depth up to 3 m. Both can trace an energised or de-energised conductor without excavation [Radiodetection, 2022].

Could adding 50 cm of soil trigger problems?

Yes. Major grading changes alter drainage; neighbours may complain, and building control can order you to restore original levels [Elektroda, retrofood, post #16759347] Document the terrain change in an updated plot plan to avoid disputes.

How do I document a route change for acceptance?

Mark the new straight line on site and in red on the design copy.
Have the supervising electrician sign the deviation note.
Get the surveyor to record exact coordinates for the as-built map. These three steps satisfy the acceptance commission [Polish Building Law Art. 57].

What standards cover Polish LV underground connections?

Key documents: PN-IEC 60364 (burial depth), PN-EN 50520 (warning layers), Utility specification TOR-1-1/2019 (sand quality), and Building Law Art. 36a–57 (design deviations and acceptance).

How can I protect the cable from future digging?

Place plastic route markers at ground level every 5 m, keep GPS coordinates in your site book, and photograph each stage. London data show such records cut accidental hits by 38 % [UK Linesearch, 2021].

Edge case: what happens if water fills a conduit?

Water itself does not harm PE-sheath cables rated for submerged use, but standing water speeds sheath corrosion if the jacket is nicked and slows heat dissipation, reducing ampacity by up to 10 % [EPRI, 2018].