HCI: Frequently Asked Questions

What is the Hot Connection Indicator (HCI)?

The Hot Connection Indicator (HCI) is a brand new electrical fire safety accessory designed to highlight developing heated electrical connections to the naked eye.  They change colour from purple to pink at 55°C and will stay permanently pink if they reach 70°C.

Why Permanent Colour Change at 70°C?

70°C aligns with the maximum operating temperature of standard cable.  70°C is also before any physical deterioration of connection PVC or insulation occurs and long before potential plant breakdown or fire ignition risk.

Are HCI’s easy to fit?

HCI’s are extremely easy to fit. They simple push fit on to a cable.  No disconnection required. See our fitting instructions.

Why Purple and Pink colours?

Purple and pink colours are used because they are contrastingly distinguishable and they stand out against the usual colours that can be found within electrical boards and panels i.e. grey, brown, black, blue, red, yellow, green and white.

What size cables will HCIs fit?

HCI’s are designed to be fitted on all sized cables between 1mm2 and 70mm2 cross sectional areas as follows;

HCI H1; 1mm2 to 4mm2 csa standard cables.

HCI H2; 6mm2 to 16mm2 csa standard cables.

HCI H3; 25mm2 to 70mm2 csa standard cables &

10mm2 to 35mm2 (Meter Tails) double insulated cables.

Note; Additionally and depending on different cable manufacturers, the H3 HCI may fit onto 16mm2 csa standard cable.

Does the HCI become brittle or disintegrate at elevated temperatures?

The HCI is made of polypropylene and does not go brittle or disintegrate like PVC cable insulation at elevated temperatures.  If the temperature of a HCI rises above 160 Celsius it does start to soften / deform slightly.  The HCI has been tested to temperatures up to 250 Celsius and whereby the HCI deforms but remains on the cable.

Obviously though the point of the HCI is to highlight elevated electrical connection temperatures at the much earlier temperature of 70 Celsius. This is long before reaching the softening temperatures of the HCI.

What is the purpose of the HCI?

The HCI is primarily designed for use on electrical connections within consumer units and distribution boards for use as part of periodic visual inspection of electrical installations.  The HCI simply pushes onto a cable next to its connection terminal, no disconnection required, and will change colour from purple to pink if the connection and cable become heated.  The HCI gives early visual warning of developing high temperature connections.

Once HCIs are installed and the cover is refitted you can’t see if they have changed colour!

Once installed, HCIs are there for visual indication to the electrician at the next inspection or modification, whichever is earlier.  If a distribution board is installed correctly and to manufacturers recommendations, heated connections can take years to develop and reach temperatures capable of causing ignition.  However, heated connections can slowly develop due to metal creep within a connection and/or local enviromental changes/fluctuations (electrical load temperature changes, local disturbance/vibration).

What is the ideal application for the HCI?

The HCI is ideal for use as part of Electrical Installation Condition Reporting and inspection of electrical installations. They add the new unique safety function of permanent colour change or historic heat indication highlighting developing heated connections.

What do I do if a fitted HCI changes colour?

If the HCI colour has changed to pink (indicating real time or historic high temperature) we strongly recommend having its associated electrical connection checked for tightness and condition by an approved electrician.  Once the electrical connection has been investigated/repaired/confirmed as safe replace the pink HCI for new.

How long will a HCI last?

An HCI will last for many years though we do recommend replacing your HCI’s during periodic electrical installation inspection (usually 3 – 5 yearly).

What is unique about the HCI?

The unique benefit of the HCI is that it retains its colour change, even after cooling back to normal operating temperatures thus providing historic heat indication. The HCI can identify connection heating faults that may not be seen during real time inspections of electrical installations (visual or thermal camera) due to connections being cooled when off-load or if isolated at the time of inspection.

This really is a novel safety benefit as the majority of electrical circuits are not permanently on-load and so when off-load would allow any heated connections to cool/return to normal temperature.  An example of this is storage heaters (economy 7 heaters) whereby they are only switched on at night and off during the daytime.  Other examples can easily be realised when considering oven, shower, sockets and lighting circuit typical load variations during day/night and summer/winter.

What advantage does the HCI have over thermal camera inspections?

Thermal camera inspections, though very precise and having full temperature range, give a real-time snap-shot image of heated connections that are apparent at the time of the inspection. In the above storage heater, oven or shower scenario, the thermal camera inspection if carried out when circuits are off load would not highlight any developing connection problems as the connections would have cooled down.

What other benefits does the HCI have?

Other advantages of the HCI are; they are low cost,  they give 24/7 monitoring and they can easily be retrospectively fitted onto existing electrical connections without the need to make any disconnections.  Once fitted they can be visually inspected by an electrician or trained person at any time frequency (daily, weekly, monthly, quarterly etc).

Would a heated MCB connection operate the thermal trip in-built into the device?

Loose connections at the MCB terminal are commonplace and there are numerous instances and images available on the internet that demonstrate that when they do reach excessive temperatures they do not operate the thermal trip which is in-built into the MCB.

I'm interested in buying large quantities.

We offer price breaks for multiple purchases.  If you require large quantities (1000+) please get in touch to discuss.

Technical Questions

Why 55°C and 70°C Colour Change?

55°C aligns with the common maximum operating temperature of the switchgear.

70°C aligns with the maximum operating temperature of standard cable.

HCI Comparison Indication

The HCI’s application handle extends away from the main body and is a convenient colour activated visual comparison reference point between the pink body and the purple application handle if the HCI has been heated.  This assists easy visual identification between normal and abnormal conditions.

Electrical Insulation Testing?

The HCI is manufactured from polypropylene a natural electrical insulator and has been tested to 1000Vdc between the inner and outer faces (worst case position).

Short Term Heat Durability

The HCI is durable to short-term heating that may be caused by electrical selectivity / discrimination and will not permanently change colour unless it has been subject to temperatures above 70°C for at least 15-20 seconds (depending on the actual temperature / heat energy and the time it takes the heat to radiate into the HCI body).

Still got a question?