View Full Version : Yet another cautionary tale

Pete VanderLaan
01-09-2012, 06:41 AM
I installed Charlie's and my first moly on Dec 16th and it just really cranks at 19KW on a 135 lb pot. Then Yesterday Nathan Macomber, who kind of babysits the furnace called me up to tell me it was shut off:

So I went over there trying to figure what I might have done wrong and on arriving found the entire control panel down and the only thing running being a blower I put on the transformer. It was on a different circuit from the panel. So, I opened the panel and the 15 AMP breaker I had installed for the circuitry was not thrown. So I tested the input to the breaker and it was dead. So, I checked the outlet into which I had plugged the breaker. It too was dead. My 240V shut off worked just fine and there was power there.

Now, I had asked the owner to put in a dedicated 115V circuit at the panel and I thought I got that but I got it in the form of an outlet box, so I used it since I had the breaker inside my own panel. Code simply requires ashutoff for servicing a panel and we had that in the panel.

I then followed the lines back towards the main panel in another room. I found no breakers tripped in the main panel. I went back out to the other room at that point and began to check other outlets on the wall behind the gloryhole and the pipe cooler. I noticed that the Digitry was down as well. Testing these outlets proved to show no power to any of those appliances. I still had the little blower chunking along just fine at the transformer, so, I plugged the circuitry and cooling blowers for the elements in there. It fired right up.

I asked Nathan to look at what I was seeing and he agreed that no breaker had tripped at all and agreed that the outlet box behind the control panel was really really loose on the wall with the receptacle loose as well.

My hunch is that there is a loose wire in that box and that the electrician wired in such a fashion as to run the hot leg in to the outlet and picked up his hot leg from the other wire in the back of that receptacle and kept on going. So, when the first wire broke, that knocked down the whole circuit. Again, I had thought up until this point that the circuit was dedicated.

It is possible that the breaker in the main panel is faulty but I doubt it. The bad connection could be there too. While I did not count AMPS from all the appliances on the circuit, I don't see how they could have exceeded 20AMPS, the breaker size. It's possible too that there is a short on one of those appliances but that is something I could not determine. I did not want to throw the breaker to check it since I want the owner to see it exactly as I found it. People can get very pissy on liability.

I did not attempt to fix the wiring problem . I'm not a licensed electrician and I don't want to be blamed for the wiring issue since it has potential serious repercussions for the crucible which is 3/4 filled with glass. I would not however want to be the electrician right now.

So, the cautionary part of the tale is, when someone says you have a dedicated circuit try to find out if that's actually true. It still could have a bad wire and this ran for three weeks before presenting itself. If I had been able to hardwire the circuitry, it would not have happened since I would have just had wires at the junction box and not a covered box.

But the furnace is beautiful as is the panel. Charlie did a beautiful job. It cruises up to 2350F if you so desire. I'll take some pictures

Steven O'Day
01-09-2012, 09:39 AM
I had a similar problem, it was a GFCI gone bad?

Pete VanderLaan
01-09-2012, 10:12 AM
I have been up there since I posted this and there was in fact a GFIC behind his bench. The owner has the digitry, the furnace, a pipe cooler and a gloryhole all on the outlet I thought was dedicated to the furnace function only. While I still don't know what tripped the GFIC after three weeks, I know I want a dedicated circuit for the control panel and I have advised the owner that I think he would be wise to get the digitry on a dedicated circuit as well.

He just has all his eggs in one basket. We have the furnace back up at about 880F at this point and climbing to 1000F where I intend to hold it for 8 hours and then advance to 1100 over another 8 hours, hold again for six hours and then come up to 1300F and consider the next stage of the programming. I hate it when this happens to a new pot.

Tom Fuhrman
01-09-2012, 10:37 AM
You're lucky. think what might have happened if this was an installation a couple of thousand miles away. The owners of small shops must be aware that they should have a well trained "maintenance person" on call just like most factories have at their access.
I could see the novice a couple of thousand miles away taking you to task for not creating a piece of reliable equipment. Lucky you were close enough to troubleshoot personally. Doesn't it drive you nuts when the minor things out of your control are what upsets the entire "apple cart".

Pete VanderLaan
01-09-2012, 02:39 PM
well, it had nothing to do with the furnace or the panel. You are still right about understanding where your tools and shop actually come from. It's a problem that just keeps growing as the schools teach less and less about systems and it covers virtually everything that one should know about running a shop that people no longer seem to know at all.

Viva El Shop Tech...

This is a system that is unattended much of the time, part of the reason the owner wanted a moly and it is a lot safer than gas for obvious reasons, but if you don't do maintenance it can be much more dangerous than gas. With this, they just tried to simplify when it was not a good idea. I'm not sure how it would have been handled if it had been a thousand miles off. I would have asked if the breaker had tripped in the panel and if I was told "No I would have simply followed the same thought pattern I used, just over the phone.

I sure have been impressed with the laser thermometers. earlier in the day I had been shooting my own connections and out one jumped at over 400F! I looked closely and the wire had deteriorated at the buss block. I changed it out since it had two years plus on it and the temp dropped to 125F. That tool is 30 dollars at Home depot. While it only goes up to 600F, That's all I need.

Steve Stadelman
01-09-2012, 06:56 PM
You have NO IDEA how many hundreds of these calls I have taken and still take :)

Allan Gott
01-09-2012, 07:20 PM
pipe cooler/GFCI sounds like trouble .......we trip GFCI breakers on site all the time when it's wet and our outdoor power cords are on the ground.

When I wired my shop it took substantial effort to convince the master electrician to sign off on a panel that contained more breakers - by adding up their capacity - than the panel was rated for. His argument - "the potential" - mine - "all dedicated circuits, nobody plugs anything extra in unless I say so" - he wasn't happy, but he signed

Mark Rosenbaum
01-09-2012, 07:52 PM
You have NO IDEA how many hundreds of these calls I have taken and still take :)

...and we thank you for not forgetting about us! :)

Pete VanderLaan
01-10-2012, 05:46 AM
..and he's referring more and more of them to me. I'm running a new and different SCR and I really like it.

I agree with Alan. I saw that pipe cooler on the GFIC and immediately became suspicious. I still don't know what tripped it but I don't want my tooling on it. They are installing a dedicated circuit today. If they just take it off my dedicated 240V line I'm good It has a neutral and good ground. We are back to 1300F. I advised that they get the circuitry for the digitry off of it as well. That's a lot of eggs in a basket. Eggs...everywhere I look.

Jon Myers
01-10-2012, 01:10 PM
What do you like about the scr you are using over the watlow?

Pete VanderLaan
01-10-2012, 04:29 PM
To turn the AMPS up or down, you just turn a little dial. It does not have to be programmed, It is extremely simple and can't be misprogrammed by curious fingers. It cost $1000.00 less than the Watlow.

Pete VanderLaan
01-10-2012, 04:30 PM
To turn the AMPS up or down, you just turn a little dial. It does not have to be programmed, It is extremely simple and can't be misprogrammed by curious fingers. It cost $1000.00 less than the Watlow. It is just humming along perfectly. It has a very large heat sink. it is fan cooled. It is a lot smaller.

Alexander Adams
01-11-2012, 01:14 AM
Slightly off topic.........but since you mentioned pipe cooler, GFCI and suspicious, I thought I would ask:

Why do people continue to build/use pipe coolers that use AC instead of DC+battery powered pumps? Extension cords running across studio floors simply s^ck as does the piddle/dribble/sprinkle-down water feature that generally follows such a design. Blech!

Someone that I once worked for had one of those zen fountain, ungrounded, extension cord obstacle course things and it lived by an oven. In order to cool the pipe, one had to arch their back and thrust their hips forward so as not to touch the oven and become a conductor between oven and pipe cooler and get a shock. I do believe that everyone who made equipment for that shop tried very hard to make things the most unergonomic as possible and it showed.

Rollin Karg
01-11-2012, 05:18 AM
We've been using a Cutler Hammer Contactors for the kill switch and on the upstream side there are multiple places to tap for a 120 circuit. These circuits are then protected with a surface mount 20 amp fuse. The fuse and contactor are in a NEMA box with the SCR. It a little more efficient than bringing another circuit, especially if you start to get any distance from your panel.

Pete VanderLaan
01-11-2012, 06:20 AM
When doing it for strangers, Code is God. Code calls for a shutoff within five feet of the panel. To the best of my knowledge it is something like a heavy appliance application and that requires a dedicated circuit about which I could be wrong. I can get around that because I have a 15 AMP Breaker in the panel itself but I still want the isolated circuit because I'm cautious and lazy.

In this case, the wiring is really a mess of tangled wire in the eaves, all Romex. I don't like it. The lines look like a VanderGraf generator with a billion tendrils coming off, and it makes the Fire Chief still in me kind of hinkey. so, I want to know where my sources are . I could actually have gotten the 115V off of the dedicated 100 AMP 240 line since it brought in a neutral leg. I just don't want another shutdown like this. Building inspection up here is a very weird honor system where the contractor does his own inspecting and then the firechief comes and looks at it. Having been one, I know this to be a bad plan. No fire chief would have a clue as to what they were looking at. But we live free and die up here. They just use stock fiml footage of fires on TV

As to the pipe cooler. Mine is 115v and has been unchanged for 35 years. I took it to Pilchuck in '76 and no one had ever seen such a thing. It could certainly stand improvement. I still remember Dale pointing at one feature of it saying "That's a bad design", which was sadly true. But if it ain't broke, don't fix it and it has never been broken enough to be fixed. But it should and there goes another day. I spend less and less time on my equipment these days. If I'm building for someone else, that's different.

I was amused by the battery powered pipe coolers I saw once at GAS, They seemed perfectly nice but had a price tag of $1,200 bucks, which astonished me.

David Hopman
01-11-2012, 11:43 AM
Aquarium power heads work great on pipe coolers. $20 and they'll last a decade.

Kenny Pieper
01-11-2012, 12:07 PM
For a pipe cooler I use a 12 volt deep cell marine battery that fits under the cooler and it drives a billage pump. I charge the battery about twice a year.

Dave Hilty
01-11-2012, 04:58 PM
For a pipe cooler I use a 12 volt deep cell marine battery that fits under the cooler and it drives a billage pump. I charge the battery about twice a year.

Ditto and I can't understand how the battery can stay charged so long. Everytime you think its discharged its just the water reservoir needing to be filled...evaporaton.

Allan Gott
01-11-2012, 08:52 PM
I still remember Dale pointing at one feature of it saying "That's a bad design"

He musta loved the scuzzy 55 gallon drum with the V-shaped perforated scoop

Pete VanderLaan
01-12-2012, 06:51 AM
No, he didn't like the part which would catch on the head of your pipe. It was a bad design. Dale however said that constantly. He would walk around and point and say "That's a good design", "That's a bad design". Point. Point. He called it teaching design.

Dale actually didn't like teaching at all. Never did. We used to get out on the slab at Pilchuck to work at 4:00 AM so he didn't have to see the students. He had his good and bad points. He was very generous and he really loved his mom. He would do absolutely anything for Viola.