Detection of buried services for construction 

The purpose of this standard is to provide candidates with the knowledge and skills to safely locate buried services using the cable avoidance tool (CAT) and generator (genny). This training standard is also known as: CAT and Genny; Cable Avoidance; Avoidance of Underground Services.


Minimum half a day of 3 learning hours


The purpose of this standard is to provide candidates with the knowledge and skills to safely locate buried services using the cable avoidance tool (CAT) and generator (genny).

The scope of this standard covers:

  • HSG47 requirements
  • locator operation, theory, limitations
  • using CAT and genny locators and software
  • inspection, calibration and testing equipment
  • safe working practices
  • permit to work.

Occupational relevance

Training delivered against this standard would be relevant to the following occupational group(s):

  • operative and craft
  • supervision.

Candidate pre-requisites

There are no candidate pre-requisites as part of this standard.


As a minimum, course instructors must be able to demonstrate that, in relation to this standard, they have:

  • a train the trainer or instructional techniques course certificate
  • successfully completed training to this standard 
  • at least 2 years relevant industrial experience
  • a verifiable CV.


Delivery may be in an on or off the job environment.

All materials and equipment must be of a suitable quality and quantity for candidates to achieve learning outcomes, and must comply with relevant legislation.

The class size and candidate/instructor ratio must allow training to be delivered in a safe manner and enable candidates to achieve the learning outcomes.

The following delivery methods may be used in the delivery of this standard:

  • classroom
  • workshop

This standard is considered to contain 51 per cent or more practical learning.


For the successful completion of training, candidates must complete an end of course practical assessment or knowledge test that measures the learning outcomes and has a pass or fail criteria.

Quality assurance

Quality assurance against this standard will require initial approval of the training organisation and their content mapped to the standard. 

CITB will also conduct an approval intervention, either desk-based or centre visit, to ensure the training organisation can meet the requirements of the training standard. 

Approved training organisations (ATOs) will be required to present information on records of training and assessment upon request to CITB for desk based analysis. They will also be visited annually by the CITB quality assurance team.


Recommended refreshment: Health & Safety Executive (HSE), other relevant codes of practice or industry card scheme criteria recommend that the candidate completes a refresher of his/her training, (i.e. to ensure their knowledge and/or skills are up to date) every 5 years.

Approval date

November 2018

Review cycle

Either on request or in 3 years from approval date.

Learning outcomes

The candidate will be able to

Additional guidance to support learning outcome

Identify the key requirements of HSG47
Outline the main components of buried service plans


Describe the operation of a CAT and genny locator


Use a CAT and genny locator and software


Inspect, calibrate, and test location equipment


Describe what a permit to work is, and why it is needed for detecting buried services

'Permit to work systems' guidance on the HSE website