Three phase earthing device for HV / MV overhead lines-application from the ground or from height



Code: Msp – CAA – U – 2xSf/lf – Sp/lp – O/p  

 The three phase earthing device provided with automatic self-locking phase clamps (CAA) can be applied from the ground or from height on the MV overhead lines. This device contains two subassemblies: one for earthing, other for short-circuiting of the conductors.

The main parts of the phase clamp are made by casting from aluminium alloy. This clamp (CAA) is provided with a special coupling system for setting up on conductor and a steel ring for removal from conductor. The new coupling system allows easy and safe mounting of the clamp on the applicator. This system avoid an accidental detachment of the clamp and assures a simultaneously detachment of the clamp from the applicator along with its fastening on conductor.

If the operation should be performed from the ground, a long telescopic insulating stick (maximum length 9 meters, code: PTU-AS-400kV-6-C) could be used.

If the operation should be performed from height, a short telescopic insulating stick (PTU type) could be used. Different other options are available.

This procedure should be done respecting following operations:
1. The earthing subassembly should be applied in order to get the connection of a phase conductor to the ground.
2. After that, the short-circuiting subassembly should be applied starting by the conductor connected to the ground.

The fastening of the phase clamp is performed by hooking and pulling downward of the clamp, on conductor. At the setting up operation, an appropriate insulating stick with applicator should be used.

The removal of the phase clamp could be performed by hooking and pulling downward the steel ring of the phase clamp. At the removal operation, an insulating stick with removal fork should be used.

Technical characteristics


Earthing Sp and short-circuiting Sf  cable sections  (mm2)




Nominal short-circuiting current for t=1s Isc (kA)




Nominal peak currrent for t=0,02s Isd (kA)




Testing short-circuiting current for t = 1s Itest (kA)




Testing peak current for t = 0,02 s Ipeak (kA)




Peak factor (SR EN 61230)


Short-circuiting cable length lf  (m)

max. 4

Earthing cable length lp  (m)

max. 15

Conductor diameter on which the phase clamp can be applied (mm)

6 – 32

 This equipment contains the following subassemblies and components:

– The short-circuiting subassembly:

  • Automatic self-locking phase clamp (CAA) – 3 pieces
  • Short-circuiting cables – 2 pieces

– The earthing subassembly:

  • Automatic self-locking phase clamp (CAA) – 1 piece
  • Earthing cable – 1 piece
  • Earthing clamp – 1 piece

– Clamps applicator – 1 piece

– Removal fork (CDAU/E) – 1 piece

– Earthing rod – 1 piece

This equipment is delivered in a carrying bag or a transport case.