As has been mentioned here, LOW resistance indicates a safety problem. If the operator has resistance of less than 1 megohm (nominal) to ground, then they risk electrocution if they touch 110V hot. Without sufficient current limiting resistance, it's like having your guy standing around in a puddle of water. With one megohm resistance in series, 110 volts will give him a good shock, but the current is limited to less than 1 milliamp (I=V/R), which is not enough to stop his heart. Lotion and more sweat will lower the resistance, not increase it. You could have him wear insulating socks inside those shoes, but that won't be very comfortable and probably won't last for long, as sweat builds up. In fact, some ESD-protective shoes are deliberately built so that they don't "breathe" very well, facilitating buildup of a sweat layer. We've had issues with conductive shoes failing low, because the shoes were too conductive for some people. We replaced those shoes with ones that meet spec. If heel straps are failing as well, that's a puzzle, because something is circumventing the 1 megohm resistor. The only way this can happen is if there's another parallel path to ground. Are you testing with both feet on the conductive surface at once? The spec says to test each foot individually, because a person keeps only one foot in contact with the floor at a time when walking. If your footwear tester doesn't have independent footplates, have this person lift one foot at a time while pushing the little button. As for the wrist straps, that's another head-scratcher. If this person is wearing conductive footwear on a conductive surface while he's testing the wrist strap, there's your other path to ground. Try having him stand on an insulating pad. Joe Kane BAE Systems Johnson City, NY -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D. Sent: Wednesday, May 20, 2009 3:59 PM To: [log in to unmask] Subject: Re: [TN] ESD Heel Strap / Shoe Checker - low resistance Most shoe testers are checking for a range of 1 meg to 10 meg. Anything in between is a pass. Over 10 meg is too much resistance in series between the "touch button" and the shoe/strap floor plate, which is the operator, the sock, and the shoe or heelstrap. Under 1 meg is too little resistance between same. Most people fail high due to dry feet, loss of conductivity in the shoe, or their hands are too dry. People that fail low are unusual. If your warehouse worker is working in a warehouse that is not air conditioned and he sweats heavily his socks and his shoes can actually become saturated to the point where the reading is "too conductive" and he will fail low. Applying lotion to the strap will exacerbate the situation. If he put on someone else's shoes and walked around in them with damp socks plus the lotion is still on his socks and skin he could possibly saturate someone else's shoes, but I doubt it. If his shoes are saturated with any oils or chemicals or metal filings/nails from the warehouse or loading dock area they would also fail low. A portable ESD checker can be used to measure the actual resistance between the bottom of his shoe and his finger. If it is below 1 meg you may wish to have him wear thicker socks and make sure the heel strap is worn on the inside of his shoe, but not on the inside of his sock. I suspect that he is really failing high, in which case he may need a good foot lotion, non-acrylic (thin wool or cotton) socks, and possibly even a hand lotion. Be sure the lotion is something like I.C. lotion from R&R products or the equivalent and does not contain any silicone or lanolin. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Helena Pasquito (Cobham DES SSA) Sent: Wednesday, May 20, 2009 1:53 PM To: [log in to unmask] Subject: [TN] ESD Heel Strap / Shoe Checker - low resistance Hello Tech Net, Assemblers and techs check their shoes on an ESD Shoe checker, each day before the start of their shift. We have one person that works in the warehouse that always fails low (resistance). We have tried new heel straps, walking for an hour or two in regular ESD shoes, even wearing someone elses shoes that had just passed. Nothing seems to work. He has also tried to apply lotion to the strap that sits inside his sock. Do you know of any tricks we can try to employ? Have you seen issues like this before? I think some of the steps we took may have helped for a high resist fail but not a low resist. Even the wrist strap test fails for him (multiple wrist straps). Any suggestions would be much appreciated. Helena Pasquito Training Specialist Certified IPC Trainer Cobham Electronic Systems 1001 Pawtucket Blvd., M/S 160 Lowell, MA 01853 978-442-5024 [log in to unmask] --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------