|View single post by Keinokuorma|
|Posted: Wed Mar 21st, 2007 11:59 pm||
|A saga from a recent adventure, involving GFI...
A customer had a setup where they had run an extension cord for their washer and dryer to the basement, where they had no outlets... and it just turned out that they had done this with a simple two wire extension cord that had the plug artificially reshaped to fit the grounded outlet.
For background information, the North-European single phase plugs for the grounded and un-grounded circuits up to 16A have the neutral and live prongs at similar spacing, and the plug can be inserted either way (by definition the polarity should not matter). Anyway, the un-grounded plug is designed so that it will not fit a grounded outlet without illegal re-shaping. This is an old system designed to keep low insulation machines from being used in "wet" areas of the house, where grounded outlets are mandatory. Anyway, the grounded plug fits the un-grounded outlet perfectly although it does not get grounded. This does not readily pose a threat in a "dry" room with a correctly working machine, or so it was thought back when the system was designed.
Anyway, this customer had re-shaped the plug of the extension cord, to make it fit the outlet at the porch... then the cord was run through a ventilation hole to the basement where they operated the machines... turned out they had been doing so for twenty-some years wih nobody paying attention. They house had electrical renovation done some five years ago, but they didn't bother have the basement done, anyway the porch circuit was equipped with GFI in the process. The twenty-some year old washer and dryer worked satisfactorily (at least to an extent) until lately.
Their son had visited them recently, and by chance noticed their setup. He told them they will have to use a proper grounded extension cord for their safety. What he didn't know or care to tell them was that the present code forbids such an installation altogether, where power for a "wet" system is brought by an extension cord from another area of the home. He got them a 5 metre cord, they started using it... soon after they called in the electrician that a friend of theirs happened to know. By chance that was me.
Well, I went there, they explained that recently their washer and dryer have been tripping the breaker every now and then. And, they told that it must be something wrong with the extension cord their son brought them... they showed me the old one and said that everything was fine with it.
SO... my first observation was that their son was right to tell them to replace the cord. It was illegal for starters, and the somewhat legal cord readily pointed out the problem that the illegal one kept hidden: Their washer and/or dryer had insulation problems. Using them on an ungrounded circuit could have one day caused a medical problem. Perhaps using them on a grounded non-GFI circuit could have developed to trouble with the fire insurance... we didn't wait for the outcome. For the heck of it, I meggered out the new extension, which turned out perfectly good.
So it was left to the washer and dryer. Good to notice they were the domestic UPO brand... perhaps that made them through the 2+ decades. Examining them I noticed that the concrete under the washer had a puddle of water, and was deeply impregnated by water too. No fresh spill, this had been happening for a while. Also they had an old vented dryer that wasn't vented anywhere. So it was just circulating the moist air in the cramped room. Also for the heck of it, I tried them out on the old cord, and was able to read 0,02A on the clamp-on meter by clamping it over the cord... on the fringe of tripping the GFI even without the ground contact. Both machines were really noisy too, especially the dryer which screamed MDK.
I told the old man it is in their best interest to get a new set altogether, have a dedicated circuit for them wired in the basement, which I could do, and either vent the new dryer through the hole that was used for the cord, but perhaps they shoud get a condenser dryer.
Well these people were nice and accepted the proposition, we have contracted the wiring job for Friday and they said they will shop for new machines at the end of the week too. I proposed them to go on with UPO as they still seem to be well made if looking into the repair statistics.
Whoops this is a laundry appliance repair adventure (LARA), but I added it here to join the rest of the GFI stuff.
Last edited on Thu Mar 22nd, 2007 12:09 am by Keinokuorma
"There is no reason anyone would want a computer in their home."
- Ken Olson, Digital Equipment Corporation (1977)