One Liners issue 63 - January 2009

Standards of electrical safety need to be much higher in a medical location than in a domestic or commercial environment. MHRA receive a significant number of reports each year resulting from misunderstandings or poor practices associated with failure to comply with good electrical management. This has the potential for injury to both patients and users.

This issue of One Liners is concerned entirely with common problems that have been encountered in an attempt to highlight good practice in relationship to electrical circuitry and how associated injury to patients or users can be avoided or addressed.

Down to earth
When several earthed medical devices are used close to a patient, it is important that their earths are at the same electrical potential. If not, there is a risk of electric shock to the patient.

• Connect all devices to fixed mains sockets, if possible. If an extension cable must be used, use only one and limit the number of devices connected to it. Purchase only good quality mains extension cables.

Don't mix it
If devices make conductive connections to a patient, eg, diathermy, ECT, EEG, they should be powered from the same type of mains supply.

• Having some devices supplied from an isolated power supply (IPS) and others supplied from the normal hospital mains, may lead to problems.

Live wires
A hospital staff member received an electric shock when connecting a plug-in mains lead to an infusion pump. The insulation had become pulled back at one end, exposing the copper conductors.

• Mains leads can become damaged in use and should be regularly checked. Any faulty or damaged leads should be taken out of service, reported and replaced.

Not to standard
A supplier claimed that their mains extension leads complied with the electromedical safety standard BS EN 60601-1.

• This standard is designed for electromedical devices and equipment only and does not apply to mains extension leads, which are part of the mains supply.

Non transferable
Never swap plug-in mains leads between devices as leads correctly sold with non-earthed equipment may have no earth connection.

• If such leads are transferred to devices intended to be earthed, there is a risk of shock.

Hot sockets
Always turn off electrical equipment before unplugging or the mains plug and socket can be damaged by arcing.

• Switch off at the device if possible and at the mains socket to avoid such damage.

For further advice see MHRA poster “Shocking Trips”

The One Liners Editions are published by the MHRA, an executive agency of the Department of Health.
Adverse incidents should be reported at the earliest opportunity. We prefer to receive reports via the online reporting system on our website www.mhra.gov.uk.
You may also use this online system to send an e-mail copy of your report to your medical device liaison officer.
We also have an adverse incident hotline: 020 7084 3080. You can find detailed reporting guidance on our website.