# Cabling Recommendations

Use unshielded, high-quality twisted pair communication cable with low capacitance, such as Category 5 (CAT5) or better (CAT5e or CAT6).  In noisy environments, shielded cables can be used.

However, using shielded cables where unshielded is specified can reduce the maximum cable length by up to 25%.  Multi-strand cables improve flexibility, and screened (shielded) cables reduce interference.  However, increased capacitance from shielded cables can reduce the maximum distance.

* Check cable type, size and maximum distances
* Pull cables for all inputs and outputs
* Check device power requirements

The HBUS protocol allows communication over distances up to 500 meters (1640 feet). This is beneficial for large installation where devices are spread out but ensure that the cables used support the required impedance, 120 ohms, particularly if you are dealing with long distances.

### Cable distance

<table data-full-width="false"><thead><tr><th width="186">Cable type</th><th width="152">Cable format*</th><th width="265">Single HBUS device – data only</th><th width="164">Single HBUS device – data and power</th><th width="171">Multiple HBUS devices – data only</th><th width="100">Multiple HBUS devices – data and power</th></tr></thead><tbody><tr><td>CAT 5e or better**</td><td>4 twisted pair<br>Each 2 x 0.2 mm2 (24 AWG)</td><td>500 m (1640 ft)</td><td>50 m (165 ft)</td><td>500 m (1640 ft)</td><td>50 m (165 ft)</td></tr><tr><td>SEC472</td><td>4 x 0.2 mm2<br>Not twisted pairs (24 AWG)</td><td>400 m (1310 ft)</td><td>50 m (165 ft)</td><td>–</td><td>–</td></tr><tr><td>SEC4142</td><td>4 x 0.4 mm2<br>Not twisted pairs (21 AWG)</td><td>400 m (1310 ft)</td><td>100 m (330 ft)</td><td>–</td><td>–</td></tr></tbody></table>

<figure><img src="/files/2gnjOKHaMjmOnY7OE9zQ" alt=""><figcaption></figcaption></figure>

\* The matching of wire sizes to equivalent wire gauges are only approximate.\
\*\* Recommended cable types for optimal HBUS RS485 performance.

{% hint style="warning" %}
Shielded cable may reduce the obtainable cable length.&#x20;

Shielded cable should be grounded at the Controller end only.
{% endhint %}


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