What a cable trench cover actually is
A cable trench is the shallow concrete or brick-lined channel that runs alongside substations, industrial parks, railway platforms and tunnel walls to carry power and telecom cables. The part most buyers actually need to precast in volume — and the part this guide covers — is the removable concrete cover slab that seats on top of that trench. It has to protect the cables, carry foot or light vehicle traffic, and still lift out when a crew needs to pull new cable or inspect the run.
That last requirement drives the design. Unlike a fixed drainage slab, a cable trench cover is opened repeatedly, often for decades. So the mould is built around lift points — moulded lifting slots (a common size is 8.5×3.5cm), recessed handles, or through-holes for a hook — plus a seat that locates the slab on the trench wall without rocking.
The four cover families we mould
- Lift-handle power / utility covers. The workhorse for substations and utility corridors. Rectangular slabs from roughly 60×40cm up to 170×50cm, with moulded lifting slots or pull points. Typical specs include 80×50×6, 74×40×8, 72.5×50.5×5.5 and the wide 170×50×8 power cover.
- Notched and treaded covers. Notched variants (e.g. 71×49×8, 79×50×6 with a 20×1cm notch, 89×49×8) have a moulded side notch for frame or pipe clearance. Cobblestone-tread covers (e.g. 138×40×5) and Tie-Biao striped covers (70×43×6) add anti-slip surface for walk-overs and rail-side trenches.
- Metro / subway covers. Large smooth ABS panels such as the 149×55×5 metro cover, plus multi-part T-junction assembly sets (e.g. 60.8×59×34.4cm) supplied with a demoulding diagram, used where trough runs branch on a platform or underpass.
- Deep-burial tunnel covers. Extra-thick 20–26cm slabs for railway and road tunnel troughs — 60×50×26, 80×50×23 and the 85×49×20 type-B section — engineered to tunnel drawings.
You can see all of these with dimensions on the cable trench cover moulds product page.
How to size a cover from your trench (the most common mistake)
Buyers frequently send the trench inner width and assume that is the cover width. It is not. The cover has to overhang the wall to form a bearing seat on each side. A 170×50cm cover typically seats over a much narrower trench opening — the extra width is the two seat bearings plus any frame. To size correctly, send:
- the trench clear opening (inner width × inner depth);
- the wall/seat width at the top, so the cover bearing length is known;
- the required cover thickness (driven by your load environment, not by us);
- whether slabs should be single-span across the opening or split.
Get the seat wrong and the slab either rocks (too narrow, no bearing) or won't drop in (too wide, binds on the frame).
Notches, lifting slots and treads — moulded, never cut
A frame-clearance notch, a drainage slot or a lifting hole must be formed by the mould, not ground or cut on site. Cutting a notch into a cured slab cuts the rebar cover and creates a crack initiation point right where load concentrates. The same applies to anti-slip treads: cobblestone and striped patterns are moulded into the top face so the slip resistance is integral, not a coating that wears off. If your cover needs an orientation mark (so crews don't seat it upside down), we can mould an UP arrow into the face.
PP vs ABS: which to specify
Polypropylene (PP) is the default and lower-cost choice. It flexes slightly, demoulds cleanly and is ideal for standard lift covers up to about 80cm in high-cycle yard production. ABS is stiffer and more rigid — specify it for large panels (100–170cm), the 20–26cm deep tunnel sections, and metro T-junction assembly sets, where the mould has to hold a precise multi-part geometry through hundreds of pours. As a rule of thumb: everyday removable cover in PP; big, deep or assembled section in ABS.
About load ratings — read this before you ask for one
We mould the concrete form; we do not stamp a load class onto it. Whether a cover carries foot traffic, a pickup or a service truck depends on the finished reinforced concrete — the rebar design, concrete grade and slab thickness — not on the plastic mould. We provide the geometry, wall/rib layout and thickness your drawing calls for; the structural rating is certified by the precaster's concrete design. If a project spec cites a load class, send that and we confirm the mould can produce the required section.
What to send for a fast, accurate quote
- Cover length × width × thickness, plus the trench clear opening and seat width.
- Type: lift-handle removable, notched, cobblestone/striped tread, metro panel or deep-burial tunnel slab.
- Lifting-slot or handle positions, any notch or drainage slots, and any orientation marking.
- Application: substation/power, telecom, industrial park, metro/subway, or railway/road tunnel — this drives our PP/ABS recommendation.
- Material preference, quantity by size, destination port, and whether mixed sizes ship together.
For OEM sections, a dimensioned drawing is best; clear photos from several angles work for a feasibility check. Trench body (U-channel) moulds are a separate range — see the drainage channel / U-channel moulds page.
Frequently asked questions
Do you sell the trench body or just the cover moulds?
This range is the cover programme — removable lift-handle and metro/tunnel covers. U-shaped trench body moulds are a separate, section-quoted range; tell us if you need both and we will quote the body from your section drawing.
Why do cable trench covers have lifting slots?
Cable trenches are opened repeatedly for cable pulling and inspection. Moulded slots or handles (commonly 8.5×3.5cm) let a crew lift the slab with a hook or bar and seat it flush again, with no cast-iron frame to rust or seize.
What cover size fits my trench opening?
The cover is wider than the clear opening because it overhangs to form a bearing seat on each wall. Send the inner opening, the wall/seat width and the required thickness — for example a 170×50 cover suits a narrower opening — and we match the mould.
Can the cover have a notch or anti-slip pattern?
Yes. Notches, drainage slots, lifting holes and cobblestone or Tie-Biao striped treads are all moulded in. They must be moulded rather than cut on site, since cutting a cured slab damages the rebar cover and starts cracks.
Should I choose PP or ABS?
PP for standard lift covers up to around 80cm and high-volume yard production; ABS for large 100–170cm panels, 20–26cm deep tunnel sections and metro T-junction assembly sets that need a stiffer, dimensionally stable mould.
Can you certify a load rating?
Load class is a property of the finished reinforced concrete (rebar, concrete grade, thickness), not of the plastic mould. We produce the section your drawing and load spec require; the structural rating is certified by the precaster's concrete design.