Is it allowed to cross the fire water supply with an electric cable?
We install the cable line in the workshop. Faced with the fact that the cable line intersects with the fire water supply. Do we have the right to cross this water supply? Fire water supply is under pressure.
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Hello! The answer is in PUE 7 - 2.1.56:
“When crossing unprotected and protected wires and cables with pipelines, the distances between them in the light should be at least 50 mm, and with pipelines containing combustible or flammable liquids and gases, at least 100 mm. When the distance from wires and cables to pipelines is less than 250 mm, wires and cables must be additionally protected from mechanical damage at a length of at least 250 mm on each side of the pipeline. When crossing hot pipelines, wires and cables must be protected from high temperatures or must be of suitable design. ”
However, the nuances depend on the cable line voltage and the laying method, for example, when laying cable lines with voltage up to 220 kV in the ground in PUE 7 2.3.95:
“When the cable lines cross pipelines, including oil and gas pipelines, the distance between the cables and the pipeline must be at least 0.5 m. It is allowed to reduce this distance to 0.25 m provided that the cable is laid at the intersection plus not less than 2 m in each direction in pipes.
When crossing a cable oil-filled pipeline line, the distance between them in the light should be at least 1 m. For cramped conditions, it is allowed to take a distance of at least 0.25 m, but provided that the cables are placed in pipes or reinforced concrete trays with a lid. "
And 2.3.96:
“When crossing cable lines up to 35 kV of heat conduits, the distance between the cables and the overlap of the heat conductor in the light should be at least 0.5 m, and in cramped conditions - at least 0.25 m. Moreover, the heat conduit at the intersection plus 2 m each the side of the outermost cables must be insulated so that the temperature of the earth does not increase by more than 10 ° C in relation to the highest summer temperature and by 15 ° C in relation to the lowest winter.
In cases where these conditions cannot be met, one of the following measures is allowed: burial of cables to 0.5 m instead of 0.7 m (see 2.3.84); the use of a cable insert of a larger cross section; laying of cables under the heat conductor in pipes at a distance of at least 0.5 m from it, while the pipes must be laid so that the cables can be replaced without excavation work (for example, putting pipe ends into chambers).
When crossing the oil-filled cable line of the heat conduit, the distance between the cables and the overlap of the heat conduit should be at least 1 m, and in cramped conditions - at least 0.5 m.At the same time, the heat conduit at the intersection plus 3 m to each side of the extreme cables must be insulated so that the temperature of the earth does not rise by more than 5 ° C at any time of the year. "
And also 2.3.88:
“In parallel installation, the horizontal distance in the light from cable lines with voltage up to 35 kV and oil-filled cable lines to pipelines, water supply, sewage and drainage should be at least 1 m; to gas pipelines of low (0.0049 MPa), medium (0.294 MPa) and high pressure (more than 0.294 to 0.588 MPa) - at least 1 m; to high pressure gas pipelines (more than 0.588 to 1.176 MPa) - at least 2 m; to heat pipes - cm. "
It follows that you can pave the line, subject to the above conditions.