Welcome Guest! The IOSH forums are a free resource to both members and non-members. Login or register to use them

Postings made by forum users are personal opinions. IOSH is not responsible for the content or accuracy of any of the information contained in forum postings. Please carefully consider any advice you receive.

Notification

Icon
Error

Options
Go to last post Go to first unread
Admin  
#1 Posted : 21 October 2009 15:22:00(UTC)
Rank: Guest
Admin

Posted By Martin J Morley HSE have just put out guidance about the safe use of these trolleys. See http://www.hse.gov.uk/se...ucation/safety121009.htm for the 'full' details. So what is there inside these trolleys that is so dangerous? I used to work with studio electronic flash units with 5000 joules of capacitance, without any incidents from the power packs. I had assumed, possibly as some of the manufacturers also had, that these trolleys were merely extension leads on wheels. This incident and the HSE warning suggest something more complex - but how does just switching off the socket prevent a possible incident? They say that an investigation was carried out into an electric shock incident involving a laptop charging trolley that had been presumed to be a static discharge, but was strong enough to hospitalize the teacher. This investigation apparently found there was "sufficient stored electric charge on the pins of the plug to give the user an electric shock." The key recommendation seems to be that the socket should be switched off before removing the plug, but the quote above suggests that there is still the possibility of danger. If there is capacitance, then surely the units need rebuilding to ensure adequate discharge? Are there any electronics expert out there who can shed some light on this? martin
Admin  
#2 Posted : 21 October 2009 19:33:00(UTC)
Rank: Guest
Admin

Posted By Paul Skyrme Martin, I have already written to HSE following this. I await their response. Paul
Admin  
#3 Posted : 22 October 2009 13:27:00(UTC)
Rank: Guest
Admin

Posted By Bob Howden A similar (or the same) accident is covered in a RoSPA e-bulletin for the education sector. It provides a little more information about the incident and subsequent investigation. Found it just be doing a simple search on Google.
martinm  
#4 Posted : 29 October 2009 12:32:59(UTC)
Rank: Forum user
martinm

I have just spoken with the HSE; it seems that time is of the essence. The reason for switching off the socket was to increase the time before handling the plugtop where a residual charge might be lurking. 5 joules is the fatal dose, these were carrying 'much less' even after 1 second. There may have been underlying design issues - like they weren't - but asking the manufacturer will provide a higher degree of accountability. So, chack with the maufacturer, read the instructions and don't be in too much of a hurry to hold the pins of the plug and you should be safe. martin
Users browsing this topic
Guest
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.