Residual Current Measurement Cable with Segmented Protective Conductor

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Solution Overview

Problem

Existing electrical device connection lines for residual current measurement are not reliable when currents flow through the protective conductor due to device damage, requiring device disconnection and reconnection, and are not space-saving or cost-effective for use in cramped conditions.

Innovation Solution

An electrical device connection line with a cable sheath where the protective conductor is separated from the neutral and phase conductors at a specific point, with an overmolding and ring integration for easy measurement and protection, allowing for reliable residual current testing without disconnecting devices and reducing production costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the protective conductor is separated from the neutral and phase conductors with an overmolding and opening for measuring devices, then measurement precision and reliability are improved, but device complexity increases

Engineering Contradiction:
Improveresidual current measurement reliabilityVSAvoidcable structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The cable sheath is separated at a specific point to create distinct regions, and the overmolding segments the conductors by providing individual openings for the protective conductor versus the current-carrying conductors. This segmentation enables selective measurement of the protective conductor while maintaining structural organization.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The protective conductor is extracted from the common cable sheath at the separation point and routed through a dedicated opening in the overmolding, allowing it to be physically separated and individually accessed for measurement purposes without interfering with the other conductors.

Inventive Principle:
Principle #2Taking out (Extraction)

2Measurement precision

If a conventional plug connector with separate protective conductor routing is used, then measurement capability is improved, but the connector size becomes too large for cramped conditions and production costs increase

Engineering Contradiction:
Improveprotective conductor measurement capabilityVSAvoidconnector size
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The overmolding merges multiple functions into a single integrated component: it provides structural support, creates the separation point, forms the opening for the protective conductor, and maintains insulation. This consolidation eliminates the need for separate connector housings and complex assembly structures.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The overmolding serves multiple purposes simultaneously: it acts as a structural element, an insulating component, a routing guide for the protective conductor, and a mounting feature for measuring devices. This multi-functionality reduces the overall complexity and size compared to dedicated measurement connectors.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If the protective conductor is separated with individual overmolding, then measurement reliability is improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The cable sheath material parameters are modified at the separation point to create the overmolding with different properties (hardness, insulation characteristics). This parameter change enables the overmolding to provide both structural support and electrical insulation in a single component, simplifying manufacturing compared to assembling multiple parts.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3236542B1Electrical device connection line
Publication Date: 2020.10.21 KALTHOFF GMBH
  • EP3236542B1 patent drawingFigure 1~3

AI summary

The invention relates to an electrical appliance connection cable with a cable sheath (1) in which at least one protective conductor (2), a neutral conductor (3) and a phase conductor (4) are arranged and a coupling piece (5, 6) can be attached to each of its two ends, wherein the cable sheath (1) is separated at at least one point and the protective conductor (2) runs separately from the neutral conductor (3) and the phase conductor (4) in the separation point (7).