358 High Security Fence

What Is a 358 High Security Fence?

A high security fence is a panel system with a far tighter mesh aperture and heavier wire than standard perimeter panels, built to resist climbing and cutting. The trade calls it the 358 panel or the anti-climb panel. The 358 designation comes from the aperture in inches; in metric that is a 12.7 x 76 mm mesh aperture with a 4 mm wire diameter.

That geometry gives two concrete results. First, the aperture is too narrow to take a finger, so a climber finds no gap for a toe or a hand hold. Second, the jaws of pincers, bolt croppers and pliers will not enter it, so gripping the wire from outside and cutting it becomes practically impossible. A standard panel fence marks a boundary; the 358 panel creates real delay.

AnkaraTel supplies high security fencing from our Ostim base in two stock sizes, 200x250 cm and 250x250 cm. Panels are electrostatically powder coated in RAL 6005 (moss green).

Why Is the 358 Panel Different?

Conventional perimeter panels usually run around 5x20 cm. That aperture is wide enough to take a foot, and it lets a bolt cropper work freely. Barbed wire deters, but physically it is easy to get over and easy to cut.

The 358 panel defends on three levels. Climb resistance: a 12.7 mm aperture gives the toe of a boot nothing to stand on. Cut resistance: the 4 mm wire cannot be gripped with a hand tool through so tight an aperture. Visibility: unlike a wall or a sheet screen the panel is transparent, so guards and cameras see the ground beyond and spot an approach early. In modern security thinking, a barrier that blocks the view hides the attacker.

Rigidity is a further advantage. The tight mesh gives the panel high torsional resistance, so it does not deform easily under pushing, pulling or a vehicle leaning on it. For more deterrence, concertina razor wire along the top line adds another layer.

Technical Specifications

Where Is a High Security Fence Used?

The 358 panel is the standard wherever a breach would be serious. The main applications are these:

• Prison and detention perimeters: lines that must stop entry from outside and climbing from inside, where climb resistance comes first.
• Energy facilities: substations, distribution yards, gas and fuel stations, solar and wind plants. Both life safety and copper theft are at stake.
• Airports: apron, runway and fuel farm perimeters; the classic case for a barrier that is hard to cross yet leaves the view open.
• Military facilities and critical public buildings: ammunition depots, radar and communications stations.
• Data centres and logistics hubs: high value assets, with insurers demanding a defined perimeter standard.
• Water reservoirs, treatment plants, railway and port areas: public health and safety risks, where unauthorised entry must be ruled out completely.

Entry points need the same standard, or the gate becomes the weakest part of the line; a sliding gate for vehicles and a pedestrian gate for foot traffic are planned in the same colour and height.

Choosing the Size and What to Watch For

First comes the panel width. The 250x250 cm panel needs fewer posts over the same run and installs faster; the 200x250 cm panel follows sloping, curving and uneven ground better and lets you step the level change more often. Flat and long favours 250 cm, broken and sloping favours 200 cm.

Second comes post selection and spacing. Post centres are measured one by one against the panel width, never judged by eye. A 250 cm panel drives wind and forced entry loads into the post, so its section and foundation must not be underestimated.

Third comes the gap under the line. No gap is left beneath the panel on a security run; where needed a concrete kerb beam is poured along the line to rule out crawling underneath. A panel that stops climbing but can be crawled under makes the investment pointless.

Fourth come the surroundings. No trees, poles, containers, stacked material or parked vehicles on the outer side of the line: each one works as a climbing platform. On our free site survey within Ankara we walk the line and mark these risks.

What Determines the Price of a High Security Fence?

The first factor is panel size and running metres; total length sets the number of posts and fittings as well as panels. The second is wire diameter and mesh type; the 358 geometry carries far more wire and weld points per unit area than a standard panel, and that is the real source of the cost difference.

The third is post section and fixing method: anchored base plates and concreted posts cost differently. The fourth is connection hardware; tamper proof one way bolts and special clamps are used as the job requires. The fifth is additional layers; razor wire on top, the number of gates and any special height requests all move the total.

Finally, quantity and delivery point count. Delivery is charged; shipping is added to the order total, including deliveries within Ankara. Installation is not one of our standard services; our teams attend site only on perimeter projects of approximately 1,000 metres and above. All our prices include VAT.

How Is It Installed?

Installation quality matters as much as the panel itself. One anchoring mistake turns the best panel into a weak point. The sequence is as follows:

1. Setting out the line: the perimeter is marked with a string line and post centres measured one by one against the panel width. Corners and turns are fixed first.
2. Foundation preparation: for concreted posts a hole is dug and filled for each post. For anchored posts, the concrete pad or existing slab under the base plate is prepared.
3. Fitting the anchors: the ground is drilled through the base plate holes, the dust is blown out and a mechanical or chemical anchor fitted. An uncleaned hole never grips fully, the most common mistake on site.
4. Setting and levelling the posts: posts are fixed to plumb and their tops brought up to the string line. Anchor nuts are tightened to torque.
5. Lifting the panels: 250 cm panels are heavy and must be carried upright and balanced, by at least two people.
6. Fixing: panels are clamped or clipped to the posts. On security lines, fixings that cannot be removed from outside are preferred.
7. Closing the bottom line and checking: gaps under the panels are closed with a kerb beam or fill. Finally the whole line is walked and every fixing, anchor and level change reviewed.

Maintenance and Service Life

A powder coated 358 panel is built to last many years outdoors. Maintenance comes down to three points. First, coating integrity: knocks and scratches are touched up in the same RAL shade, because exposed steel is where corrosion starts.

Second, the fixings: clamps, clips and anchor nuts are checked yearly and anything loose tightened. On a security line one slack clamp can be enough to let a panel be lifted at the edge. Third, the ground around the line: clear weeds and scrub at the base, and stack nothing outside the line that could serve as a climbing platform. Done regularly, these three checks keep a high security fence working for decades.

Shipping and Delivery Across Türkiye

AnkaraTel ships from its Ostim base to every province in Türkiye by courier and freight. High security panels are heavy and bulky, so shipments are palletised to the running metres of the line and usually planned as a full vehicle load.

Delivery is charged; shipping is not included in the product price, and that applies to deliveries within Ankara too. Site surveys are free of charge within Ankara: our team comes to site, walks and measures the line, assesses ground conditions and climbing risks, and settles the panel, post and gate combination with you. Installation is not part of our standard scope; on perimeter projects of approximately 1,000 metres and above our installation team works on site. On smaller jobs the material is delivered with installation instructions.