Description

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What Is a Transparent Bulletproof Metering Block?

A transparent bulletproof metering block is a heavy-duty metering terminal block - also called a metering test block, test terminal block or CT test block - designed for metering cabinets and distribution panels where the wiring is exposed to vandalism, tool strikes, falling debris or deliberate electricity theft.

It connects the secondary circuits of current transformers (CT) and voltage transformers (PT) to an energy meter, relay or protection device, and gives technicians a dedicated point to short-circuit the CT loop and disconnect the meter under load. What separates this model from a standard terminal block is the cover: instead of ordinary opaque plastic, it uses a transparent, impact-rated polycarbonate shield that stays see-through for the full service life of the installation.

In short, it does three jobs at once:

It carries and terminates the metering current safely.

It lets inspectors audit the wiring 360° without disassembly.

It blocks physical attack and leaves permanent evidence of tampering.

Technical Specifications

The values below describe the transparent metering block as a configurable platform rather than a single fixed part. Confirm the final figures against your panel drawing before ordering - a full datasheet and the relevant test reports are issued with every quotation.

Parameter	Specification
Impact rating	IK10 (IEC 62262), 20 J impact capacity
Cover material	Ballistic-grade transparent polycarbonate, ≥3 mm thickness
Base housing	Polycarbonate, UL94 V-0 flame rating
System compatibility	Single-phase / three-phase (configurable)
Rated insulation voltage	690 V AC
Rated current	10 A – 120 A (customizable)
Short-time withstand current	5 kA / 1 s
Contact resistance	≤0.5 mΩ (initial)
Dielectric strength	≥3.0 kV / 1 min
Conductor capacity	1.5 mm² – 16 mm² (copper only)
Termination	Cage clamp or tubular screw with anti-corrosion coating
Ingress protection	IP65 (standard), IP67 (optional)
Operating temperature	-40 °C to +85 °C
Design life	Over 20 years
Compliance	IEC 62262 (IK10), IEC 60999-1, GB/T 14048.7, CE, RoHS

Models and Configurations

The transparent bulletproof metering block is supplied as a configurable family rather than a single fixed model, so specification and ordering can match the panel drawing exactly.

Configuration	Typical use
Single-phase test block	Residential and small commercial one-meter-per-household panels
Three-phase four-wire test block	Utility distribution cabinets, C&I metering, substation panels
6 / 8 / 10 / 12-way pole options	Matched to the CT/PT circuit count on the drawing
10 A – 120 A current rating	From light metering to high-current C&I feeds
Cage clamp or tubular screw termination	Chosen by the installing contractor's wiring method
IP65 / IP67 sealing	Indoor panels through to rooftop and tunnel cabinets
Custom logo, colour and marking	For distributor and utility house brands

Supporting accessories available on request: transparent protective covers, sealing screws, test plugs, shorting links, phase marking labels, and matching junction boxes from the same series.

Product Advantages

In the field, ordinary metering blocks fail on five counts:

1. Theft & Bypass

Bakelite and thin ABS covers crack open in seconds, leaving billing data vulnerable with no trace.

2. Mechanical Damage

Trolleys, forklifts and impact shatter IK07 covers, exposing live terminals.

3. Inspection Cost

Reading phase or torque requires opening every cabinet - labour plus arc-flash risk.

4. Downtime

Meter replacement often means de-energising load - unacceptable in critical facilities.

5. Compliance Risk

Standards now require impact ratings and tamper-evident seals; non-compliant units fail inspection.

The solution- five engineered advantages

	Advantage	Engineering	Buyer Benefit
1	IK10 Ballistic Polycarbonate Shield	Entire cover injection-molded in-house from high-density polycarbonate, min. 3 mm wall. IK10-rated to IEC 62262; absorbs 20 J impact (≈2 kg steel dropped 1 m) without cracking. Test reports available for tender/technical files. Design life > 20 years	Tool assaults, brick impacts and rough handling no longer end the block's life. Replacement rate on your metering stock drops accordingly.
2	360° Zero-Disassembly Visual Inspection	Optical-grade transparent cover keeps internal wiring, phase markings and thermal indicators readable from outside.	Verify phase sequence, meter wiring and torque marks without opening a single cabinet - removing labour cost and arc-flash risk.
3	Anti-Tamper Design, Dual Lead-Sealing Slots	Reinforced metal terminal guards paired with dual lead-sealing screw slots; sealed by the utility authority after commissioning.	Once sealed, the unit cannot be bypassed, hot-wired or modified without destroying the seal - documented, legally usable evidence of interference. Unauthorised access to critical CT/PT circuits cut off at source.
4	Continuous Testing / Bypass Under Load	Internal short-circuit bypass lets engineers short the CT secondary loop and disconnect voltage loops directly under load.	Calibrate, verify or hot-swap meters without interrupting supply. No commercial downtime, no billing disputes, no outage notice.
5	Sealed Against the Environment	IP65 as standard, IP67 optional. Anti-corrosion coated terminals; UL94 V-0 flame-retardant PC base.	Stable performance −40 °C to +85 °C in coastal humidity, chemical plants and rooftop cabinets - no annual contact cleaning or corrosion-driven re-termination.

product-1807-870

Application Scenarios

This transparent metering block is specified wherever metering equipment is reachable by the public, exposed to mechanical load, or located in a network with a history of metering interference.

Prisons, detention centres and correctional facilities - metering that must resist deliberate vandalism and attempted bypass

Metro, rail and tunnel distribution cabinets - exposed to tool strikes, vibration and falling debris

Military bases and high-security government buildings - impact-rated, tamper-evident, compliance-documented

Remote rural and high-theft-risk networks - where unauthorized metering access causes the largest revenue losses

Schools, hospitals and public buildings - where accidental impact and public access are daily realities

Parking structures and industrial yards - forklift, pallet and trolley collision risk at cabinet height

Mining and heavy industry - sustained shock and vibration loads on every metering point

Critical infrastructure - water treatment plants, telecom base stations and continuous-process plants that cannot accept a planned outage

Renewable energy plants - PV and wind metering cabinets requiring high ingress protection and temperature tolerance

Installation and Operation Notes

Commissioning. Terminate the CT/PT secondary wiring into the main circuit terminals and the meter wiring into the instrument terminals. Tighten to the torque value marked on the cover, fit the shorting links in the operating position, then close and seal the transparent cover with the lead seals.

Meter testing without an outage. Fit the test plug or shorting bars so all CT secondaries are reliably shorted, then disconnect the instrument loop and connect the test equipment. Restore in reverse order. The terminal layout follows the standard short-then-disconnect sequence, so a CT secondary is not left open-circuited during normal operation - an essential safety requirement for CT metering work.

Inspection. Phase sequence, wire status and torque markings are readable directly through the cover at a safe distance. No cover removal, no exposed live parts.

Maintenance. Wipe the cover with a damp cloth; no solvents. Check seal integrity at each scheduled route visit - a broken seal is itself the tamper evidence the utility needs.

Frequently Asked Questions

The questions below mirror what utility procurement teams and distributing engineers ask most often before placing a first order.

Q: What is a transparent bulletproof metering block?

A: It is a metering terminal block with a transparent, impact-rated polycarbonate cover. It terminates CT/PT secondary circuits to an energy meter or protection device, allows visual inspection without opening the enclosure, and resists vandalism and tampering attempts.

Q: What does IK10 mean?

A:IK10 is the highest mechanical impact rating in IEC 62262. It means the enclosure withstands 20 joules of direct impact - roughly a 2 kg steel mass dropped from one metre - without cracking or losing protection.

Q: Can it be used for both single-phase and three-phase metering?

A: Yes. The block is configurable for single-phase and three-phase four-wire systems, with pole counts from 6 to 12 ways and current ratings from 10 A to 120 A.

Q: Is the block suitable for CT and PT secondary circuits?

A: Yes. It is designed for metering and protection secondary circuits, with an internal short-circuit bypass that allows the CT loop to be safely shorted before the meter is disconnected.

Q: Can meters be replaced without switching off the power?

A: Yes. The continuous testing bypass allows the CT secondary to be shorted and the voltage loop disconnected under load, so the meter can be calibrated or replaced without interrupting supply.

Q: How does the anti-tamper sealing work?

A: The block is fitted with dual lead-sealing screw slots and reinforced metal terminal guards. Once sealed by the utility, the block cannot be opened or bypassed without breaking the seal - which remains as permanent evidence of interference.

Q: Do you offer OEM and ODM service?

A: Yes. Dimensions, terminal layout, cover thickness, pole count, current rating, logo, colour and packaging are all customizable to your specification. Technical drawings are provided before tooling, and a sample is produced before mass order.

Q: What certifications do you hold?

A: ISO 9001 quality management, CCC, CE, RoHS and UL, with product design aligned to IEC 62262, IEC 60999-1 and GB/T 14048.7. Test reports are available for tender files.

Q: What is the MOQ and lead time?

A: MOQ depends on configuration; mixed sample orders are accepted for evaluation. Samples ship in 3–5 working days, mass production in 7–15 working days.

Q: Can I get a sample before ordering?

A: Yes. Samples are supplied for testing and quality evaluation, and the sample cost can be discussed against your first mass order.

Q: How is the product packed and shipped?

A: Inner box and export carton as standard, custom packaging for OEM. Shipping by express, air or sea from Ningbo / Shanghai, with full export documentation.

Q: What warranty do you provide?

A: Warranty terms are confirmed per order against the configuration and destination market; our engineering team supports installation consultation, application advice and troubleshooting throughout the product life.

product-1807-870