Alistair I have looked again at TA89/05 in 3.1 (iv) it appears to only specify NE or LE for traffic signal posts. HE can be only be used for signs or road lighting. My concern is after seeing accidents with signal poles laid flat and heads ripped off leaving live wires exposed, we need to have electrical isolation even if the pole does not shear. Personally I would prefer the pole to stay where it is. I agree it is confusing, so let me know if I've misinterpreted the specification. More guidance from the Highways Agency would be helpful. Regards Carole. -----Original Message----- From: tcug-bounce@xxxxxxxxxxxxx [mailto:tcug-bounce@xxxxxxxxxxxxx]On Behalf Of Gollop, Alistair J Sent: 14 June 2007 10:07 am To: tcug@xxxxxxxxxxxxx Subject: [TCUG] Re: Passively safe poles Carole Having had an opportunity to use a few different types of poles, I would suggest that, as you have found from your practical experience, that the mix of equipment for different applications needs to be looked at carefully. There would appear to be two types of solution commercially available at this time in the UK for electrical isolation of the poles, the Snatch-plug and the Electrical Isolator. It may be found that one of these is better for poles which are designed to breakaway, whereas the alternative may be preferential for poles which yield.=20 The use of Crash-friendly products is gradually spreading, with the realisation that they are an additional tool in the signal engineers design toolkit, but until a consensus is reached amongst the signal engineering community, about how different mixes of products should be utilised it will continue to cause confusion and misunderstanding. In answer to the previous question regarding the use of passively safe short poles, the TA specifies that poles used in the vicinity of where NMU's are likely to be, must not be Non-energy (N.E.)Absorbing types, but Low-energy (L.E.) and High-energy (H.E.) are permissible. Taking this into account, if an errant vehicle were to strike it, it would be unlikely that the pole would "fly off", but instead yield in front of the vehicle. An electrical isolator system is still required for ELV circuits on Crash-friendly poles.=20 regards Alistair Gollop MIHIE, MIET, Traffic Signal Engineer Mott MacDonald Ltd, Stoneham Place, Stoneham Lane, Southampton, SO50 9NW Office: 023 8062 8725 Mobile: 07717 224366 Fax: 07092 218790=20 Email: alistair.gollop@xxxxxxxxxxx This message is from Mott MacDonald Limited, registered in England number 1243967. Registered office: St Anne House, 20-26 Wellesley Road, Croydon, Surrey, CR9 2UL, England. -----Original Message----- From: tcug-bounce@xxxxxxxxxxxxx [mailto:tcug-bounce@xxxxxxxxxxxxx] On Behalf Of Probert, Carole Sent: 14 June 2007 08:25 To: 'tcug@xxxxxxxxxxxxx' Subject: [TCUG] Re: Passively safe poles Yes we have installed standard short poles with a termination door with the DOT plug, and it is necessary to disconnect ELV. That said we have had a couple of 4m knock downs on high speed roads and the plug and socket have not pulled apart because the aluminium poles did not shear. We now use the NAL system, which disconnects even if the pole doesn't shear, and we consider it has much greater maintenance benefits. This system leaves existing cabling connected as normal, and thus tethers the pole. If you require further information give me a call. Regards Carole Probert Traffic Signal Design Team Leader AmeyMouchel (Area 9) Tel: 01905 683219 Featurenet: 7969 3219 Mobile: 0774 871 2946 =20 -----Original Message----- From: tcug-bounce@xxxxxxxxxxxxx [mailto:tcug-bounce@xxxxxxxxxxxxx]On Behalf Of Oliver David B Sent: 13 June 2007 10:32 am To: tcug@xxxxxxxxxxxxx Subject: [TCUG] Passively safe poles Regarding passively safe signal poles. On standard and 6m poles the dot plug system is commonly used for electrical connection so that the connection breaks away when the pole snaps. Has anyone installed short poles (2m) to house a solitary PB unit and, if=3D so, is it necessary to specify a wide based pole so that DOT plug can be used=3D for disconnection, or is it considered unnecessary from an electrical safety po=3D int of view to disconnect ELV. That obviously leaves out the fact that, should the pole shear on impact th=3D ere seems to me to be a significant danger of the free pole, weighted by the PB, travelling through the windscreen with obvious consequences. That begs the question, notwithstanding the argument about the validity of passively safe poles as a whole, as to whether short poles should be passiv=3D ely safe. Any feedback/info would be appreciated. Thanks Dave Oliver Traffic Signals Manager Highways & Traffic Signals Website address www.newcastle.gov.uk Engineering Services Newcastle City Council Stratford House Phone +44 (0)191 278 3934 Newington Road East Mobile +44 (0)797 6122403 Newcastle upon Tyne Fax +44 (0)191 278 3805 NE2 1PX e-mail david.b.oliver@xxxxxxxxxxxxxxxx ----------------------------------------------------------- A message from the TCUG mailing list. For information about the list visit //www.freelists.org/webpage/tcug ********************************************************************** CONFIDENTIALITY NOTICE: The information in this e-mail is confidential and intended to be solely for the use of the addressee(s) and may contain copyright and/or legally privileged information. If you are not the addressee (or responsible for delivery of the message to the addressee) please e-mail us at postmaster@xxxxxxxxxxxxxxx and delete the message from your computer: copying, distribution, use or disclosure of its contents is strictly prohibited. As Internet communications are capable of data corruption no responsibility is accepted for changes made to this message after it was sent. For this reason it may be inappropriate to rely on advice contained in any e-mail without obtaining written confirmation of it. In addition, no liability or responsibility is accepted for viruses and it is your responsibility to scan attachments (if any). Please note that for business purposes, outgoing and incoming emails may be monitored and recorded in accordance with our Email policy. This includes scanning incoming emails to detect viruses. AmeyMouchel is the trading name of the joint venture between Amey Infrastructure Services registered office The Sherard Building Edmund Halley Road Oxford OX4 4DQ registered in UK 3612746 and Mouchel Parkman Services Ltd registered office West Hall Parvis Road West Byfleet Surrey KT14 6EZ registered in UK 1686040 ----------------------------------------------------------- A message from the TCUG mailing list. For information about the list visit //www.freelists.org/webpage/tcug ----------------------------------------------------------- A message from the TCUG mailing list. For information about the list visit //www.freelists.org/webpage/tcug ----------------------------------------------------------- A message from the TCUG mailing list. For information about the list visit //www.freelists.org/webpage/tcug