The photo shows a standard box for grounding of single-core cable screens. Such boxes are placed close to the cable terminations. Looking at the photo, we can see that the lid of the box has about 30 bolts. The question arises – do we really need this? The answer is no, we don’t need it. Moreover, such a great number of bolts is even harmful. Let’s discuss it.

There are two types of grounding boxes:
1️⃣ A box for direct grounding of screens.
2️⃣ A box for placing the surge arresters (SA) protecting the outer sheath of the cables (such a box is needed in the case of the screens’ one-side grounding).

Both boxes are installed above the ground near the cable terminations, and as a rule in places where only specially trained electrical personnel have access. This personnel is well aware of what the purpose of the box is, and that there may be an electrical potential inside the box (if the box has a SA, instead of direct grounding). Then what is the point of closing the box not by 4 bolts (at the corners of the lid), but by 30 bolts placed around the perimeter of the lid?

Maybe the manufacturer of the box is afraid for the box tightness and therefore made a lot of bolts? There is no reason to be afraid, since:
✅ Box is installed above the ground, which eliminates flooding of the box (unlike the cross-bonding box, which is located underground and really needs to be 100% sealed).
✅ The connecting wires between the terminations and the box enter the box from below, which eliminates the penetration of water into the box.
✅ Box inside has insulators and surge arresters with ribs, i.e., they are designed to work in the open air without overlaps on the surface.

We can see, there is no special reason for 30 bolts. I suppose, the only reason is that the manufacturer was too lazy to develop a separate housing for simple grounding box (installed above the ground) and advanced multibolt cross-bonding box (intalled under the ground).

So, universal box is convenient for the manufacturer. But what about the electrical personnel? This multibolt box is very inconvenient for the personnel, because during each test of the cable line and its outer sheath (DC 10 kV, 1 min), the personnel have to open many bolts of the lid, and then tighten them back.

What conclusion can be drawn? Please reduce the number of bolts.