Singles and Data in the same Dado trunking compartment

Stuart Urban said:

What are peoples thoughts on mixing 230V 6491B singles and standard structured wiring data cables in the same compartment of Dado trunking.

Not to be done for indoor ICT (telephone, data, PoE and other digital controls) cabling, according to BS 6701.

Being in the same compartment is notionally fine according to Parts 4 and 5 of BS 7671, BUT it's unlikely to conform to BS 6701, Clause 5.4.4.2, which requires at least 50 mm physical separation (but in some circumstances can be > 150 mm), even if there is a metal separator:

5.4.4.2 Protection of telecommunications cabling and attached equipment

NOTE: The following requirements represent the “Local regulations for safety” referred to in BS EN 50174-2:2009+A2:2014, 6.1.

Telecommunications cabling shall not be installed in any compartment of a cable management system that contains LV electricity supply cabling with unenclosed live terminals.

Telecommunications cabling and LV power supply cabling shall be separated by a distance:

a)≥150 mm;

b)≥50 mm, where the separation is provided and maintained by a partition as specified in BS 7671; or

c)50 mm where one or more of the following conditions are met:

1)the LV electricity supply cables are enclosed in a separate conduit or trunking which, if metallic, is bonded in accordance with BS 7671;

2)the LV electricity supply cables are of a mineral-insulated type;

3)the LV electricity supply cables are of an earthed armoured construction;

4)the LV electricity supply cables are of a flexible, insulated and sheathed type (e.g. “kettle leads” supplying LV mains power to telecommunications equipment in cabinets)

Where telecommunications cables and the electricity supply cables cross and there is a risk of damage, mechanical protection shall be provided at the crossing point.

As the Clause notes, this is for safety.

Is there a problem with conformity to BS 7671 because of this? Well, potentially. Regulation 110.1.3 tells you that you need to supplement BS 7671 with other standards, and in particular, Regulation 110.1.3 (f) tells you to use BS 6701 for telecommunication systems.

Stuart Urban said:

I have a contractor that isn't concerned by this, however even if the client agrees with a departure from BS7671 I'm still concerned from a health and safety perspective as many of the instances of this are in a medical location.

Even if it's not a medical location, CDM Regulations Designers Duties still apply, i.e. the Designer is still responsible for considering the safety of anyone repairing or maintaining the electrical installation, or the telcomms installation, in the future ... regardless of whether this is a notifiable project.

Not conforming to Clause 5.4.4.2 of BS 6701 when it specifically has the NOTE that the distances are provided for reasons of safety isn't really a good place to be in if something were to go wrong later.

Stuart Urban said:

What are peoples thoughts on mixing 230V 6491B singles and standard structured wiring data cables in the same compartment of Dado trunking.

Not to be done for indoor ICT (telephone, data, PoE and other digital controls) cabling, according to BS 6701.

Being in the same compartment is notionally fine according to Parts 4 and 5 of BS 7671, BUT it's unlikely to conform to BS 6701, Clause 5.4.4.2, which requires at least 50 mm physical separation (but in some circumstances can be > 150 mm), even if there is a metal separator:

5.4.4.2 Protection of telecommunications cabling and attached equipment

NOTE: The following requirements represent the “Local regulations for safety” referred to in BS EN 50174-2:2009+A2:2014, 6.1.

Telecommunications cabling shall not be installed in any compartment of a cable management system that contains LV electricity supply cabling with unenclosed live terminals.

Telecommunications cabling and LV power supply cabling shall be separated by a distance:

a)≥150 mm;

b)≥50 mm, where the separation is provided and maintained by a partition as specified in BS 7671; or

c)50 mm where one or more of the following conditions are met:

1)the LV electricity supply cables are enclosed in a separate conduit or trunking which, if metallic, is bonded in accordance with BS 7671;

2)the LV electricity supply cables are of a mineral-insulated type;

3)the LV electricity supply cables are of an earthed armoured construction;

4)the LV electricity supply cables are of a flexible, insulated and sheathed type (e.g. “kettle leads” supplying LV mains power to telecommunications equipment in cabinets)

Where telecommunications cables and the electricity supply cables cross and there is a risk of damage, mechanical protection shall be provided at the crossing point.

As the Clause notes, this is for safety.

Is there a problem with conformity to BS 7671 because of this? Well, potentially. Regulation 110.1.3 tells you that you need to supplement BS 7671 with other standards, and in particular, Regulation 110.1.3 (f) tells you to use BS 6701 for telecommunication systems.

Stuart Urban said:

I have a contractor that isn't concerned by this, however even if the client agrees with a departure from BS7671 I'm still concerned from a health and safety perspective as many of the instances of this are in a medical location.

Even if it's not a medical location, CDM Regulations Designers Duties still apply, i.e. the Designer is still responsible for considering the safety of anyone repairing or maintaining the electrical installation, or the telcomms installation, in the future ... regardless of whether this is a notifiable project.

Not conforming to Clause 5.4.4.2 of BS 6701 when it specifically has the NOTE that the distances are provided for reasons of safety isn't really a good place to be in if something were to go wrong later.