Hygienic cabling

Author: Ir. W.N.A. Burggraaf, Burggraaf & Partners B.V.
chairman of the National Working Group on Hygienic Cabling

The general regulation on the hygiene of foodstuffs (EU/ 852/2004) states that food premises must be clean and maintained well. The layout, design, and construction of these areas must be arranged so that cleaning and/or disinfection can be carried out appropriately.

In addition, in the preparation areas, surfaces in places where food is handled must be easy to clean. This means that smooth, washable, corrosion resistant, and non-toxic materials must be used, unless the operator can demonstrate that other materials are used are appropriate.

The surfaces that food comes into contact with are of primary importance, but the government has explicitly set additional requirements for all surfaces in preparation areas where products may be contaminated by the environment.

Cabling is used for each machine for the supply of electrical and/or pneumatic energy, but also for receiving and/or sending electromagnetic signals. Although this type of cabling does not come into direct contact with the food, it is subject to the same regulations, unless the operator can explicitly demonstrate that the currently chosen solution is sufficient.

To meet the minimum requirements, the working group on Hygienic Cabling, together with Dutch industry, has drawn up a practical guideline (only accessible when access has been bought/granted. Link to editorial with overview of Guideline content).

The main rule is:

• avoid cabling in preparation areas,
• however, if this is not possible, only use hygienic cabling.

Hygienic cabling is possible through:

• minimizing the number of cables (by combining cables in a fully enclosed cable protection tube, also called conduit)
• application of a simple and completely cleanable system

In the past, various systems have appeared on the market, which ultimately turned out not to meet the minimum hygiene requirements:

• protective tubing (conduit) snapped and broke as a result;
• cable glands damaged by cleaning agent;
• vertical cable support systems with too many cross connections, which could not be cleaned adequately;
• cable ties that were difficult or impossible to clean at the back.

State of the art

The new generation of protective tubing, cable glands, cable fixings, and cable support systems, which were developed during and after the writing of the practical guideline, have completely eliminated the hygiene problems of the past.

Protective tubing and fittings

For hygienically wet, controlled wet, and dry cleaning of the field and machine cabling, a complete package is now available on the market thanks to various suppliers.

The new Anamet protective tubes (conduits) are smooth, washable, and can no longer snap – even when they are empty – due to the special spiral wound inside. So, the tubes no longer leak, are chemically resistant, and are equipped with stainless steel fittings with hygienic sealing to the plug or box. The discussion regarding hollow spaces can now be closed (see section at the end).

Anamet has complemented its program of the hygienic Anaconda Sealtite FG protective tube (conduit) with all kinds of modular cable solutions. The Anaconda FG fitting is rated IP69K.

Because of its reduced passage width, the Anaconda fitting connects perfectly to the HARTING Han® F+B and Han Modular® multi-connector without losing any of the throughput size.

The Anaconda also offers maximum flexibility when connecting or disconnecting cable routes with Power, Data and Signal - especially during installation and maintenance.

The 90-degree angle offers the possibility for tight linking to the cabinet or connection.

Special Sealtite Anaconda T and Y pieces allow a smaller protective tube to branch off to another device. This makes it possible to combine water cooling for a video camera in a spray drying tower with the power supply and signal cable in a protective tube. Just before the camera, the water cooling is split off from the large protective tube.

It is possible to go from the Sealtite Anaconda protective tube (UL certified food grade) to a cable gland with one or more cable outlets, and to split your cables here.

The Anaconda food-grade blind plug is a hygienic seal of cable gland holes for future expansion in an electrical cabinet.

Cable fixing and cable support systems

The new, fully stainless-steel cable support system lies flat or can be perpendicular to the wall, which makes it easily accessible from all sides and is easily wet-, controlled wet- and dry cleanable by using round rungs and round springs for the cable attachment.

The Niedax Group has not been idle either; for example, the streamline HD ladder has been enhanced. In addition to good hygiene, it also has the advantages of quick installation and assembly, and of quickly installing or replacing cables or protective tubes. This is possible by means of a spring and a removable rung. Thanks to the fixation by means of a spring, cable ties are no longer necessary. This means no more risk of plastic particles.

The streamline HD cable support system is designed for cabling within a device where fewer cables need to be routed. This system also makes the cable ties that are difficult to clean unnecessary. Lastly, rerouting when replacing a cable from a field instrument can be done quickly.

An alternative to the above options, which is only suitable for wet cleaning, are mounting brackets on the frame, which can hold the cables or protective tubes. The plate thickness must not exceed 6 mm and the diameter of the hole must be at least 1 mm larger than the diameter of the cable or protective tube. The supports, connecting the mounting brackets to the machine, are welded to the brackets, so there is a closed connection.

Section: Discussion hollow spaces

Discussion hollow spaces
Some companies have a strict policy to avoid all hollow spaces. For example, all frames must be solid and protective tubes are not allowed.
The reasoning is as follows: if the integrity of the outside of, for example, a tubular frame or protective tube is compromised, uncontrolled dirt enters the hollow space which cannot be cleaned and therefore could contaminate the environment. The contamination can be either in the form of vermin or may be microbial.
The Machinery Directive explicitly states that non-cleanable areas must be hermetically sealed. This must be considered in the design, construction, cleaning and maintenance, and throughout the operating life of the equipment.
In its guideline 13 Hygienic Design of Open Process Equipment for Food, the EHEDG allows both systems: hollow and solid frame (figures 22.1 and 22.2). The welding technique at the time and the lack of discipline in the Technical Service sometimes showed that a hermetically sealed frame would nevertheless open due to cracks or drill holes. As a result, some food manufacturers have decided to stop using hollow parts. This reasoning fails to consider that solid parts can have surfaces that are not always easily accessible and therefore cannot be easily cleaned and visually inspected.
Other studies of the tubular frame show that, except in the case of snaps (visible), the tube will only tear on the weld seam if it is not sufficiently strong. New techniques with 3-D pre-lasering ensure that the forces on the inside of the pipe are supported and are no longer exerted on the weld. As a result, a frame like this never tears on the welds and the frame never leaks again. The advantage of easy cleaning and visual inspection of pipe or box parts after cleaning now outperforms the solid parts.
However, if desired, a hollow frame can be provided with an approved brightly coloured red, green, or blue dye (with E number), dissolved in a food-grade lubricant. As soon as the frame fills up with (cleaning) water, this dye is released.
The same rules apply to the new type of protective tube with hygienic fitting, which can no longer snap. It offers the same IP rating as the (hollow) junction box on the electric motor on one side and the (hollow) electrical box on the other side.