6701B or 2491B LSZH single core flex

6701B or 2491B LSZH single core flexible cable is designed for use inside equipment or as panel wire. Particularly suitable for use in public or government buildings, warehouses and computer installations due to the virtual elimination of toxic fumes if burnt. 

These 6701B or 2491B LSZH cables can also be referred to by harmonised codes H05Z-K and H07Z-K, dependent on voltage rating.

Ensures increased safety in the case of fire. Pronounced advantages when compared to a PVC sheathed cable: low fire load, low smoke emission, reduced fire propagation.

Note: low smoke zero halogen / halogen free (LSZH, LSOH, LSHF, OHLS) should not be confused with LSF (low smoke and fume), an in-depth explanation is shown on our Customer Support page.


Construction – 6701B or 2491B LSZH
stranded plain copper conductors
low smoke zero halogen (LSZH) outer sheath


Technical – 6701B or 2491B LSZH
conductor make-up: class 5 (flexible fine stranded), see Stranding/Resistance page
bend radius: 5 x overall diameter
voltage rating: H05Z-K (usually up to 1.0mm2) = 300V/500V operating
  H07Z-K (usually 1.5mm2 and above) = 450V/750V operating
current rating: as per 6701B/2491B chart, see Current Ratings page
temperature range: -15°C to +90°C operating
construction: generally according to BS7211, EN 50525-3-41
flame retardant:  according to EN 50266, IEC 60332-1-2
smoke emission:   according to IEC 61034
acid gas emission: according to EN 50267, IEC 60754-1+2
colours available: up to 25mm² = black, brown, blue, green, grey, green/yellow, 
                             orange, pink, red, violet, white & yellow
above 25mm² = black sheath only


A printable PDF specification is available here: 6701B or 2491B LSZH flexible single core cable.


A similar cable with high temperature polyvinylchloride (PVC) sheathing can be found here: Tri-rated single core 

For similar marine approved single cores return to the Other Halogen Free Cables front page.


All measurements should be considered nominal and images for illustration purposes only. Although Central Cables Ltd has made every reasonable effort to ensure its accuracy, the information contained herein is subject to error or omission and to change without notice. In no event will Central Cables Ltd be liable for any damages whatsoever, arising in connection with the information described.