Electrical Conductivity Test

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sjaniga

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Does anyone know how to test a fire hydrant system after it is installed, we were asked today if we could do it.

This is the info I have from the state web site:

Direct current of 150-amperes, shall be passed through the pipe line for a period of five minutes. Current flow through the pipe shall be measured continously on a suitable ammeter and shall remain steady without interruption or excessive fluctuation throughout the five minute test. Insufficient currnt or intermitten current or arcing, indicated by large fluctuations of the ammeter needle, shall be evidence of defective electrical cantact in the pipe line. The cause shall be isolated and corrected.

What equipment is used for this test?

Any help would be greatly appreciated.
 
Re: Electrical Conductivity Test

Yes use a dc welder of 250 amps or more. An engine drive unit with a polarity switch would be the best. The polarity switch in your case is not to change polarity but to allow you to connect the load with engine running and the DC out put off. A 300 amp Lincoln enegine drive would be perfect for this. Lincoln machines have a reactor device to control current so you can increase the current while under load to the desired value. Some Engine drive have ammeters on the panel and some dont. Check with your loacl welding supply rental house. I have used welder for this type of test many times. Columbia also makes a clamp on DC ammeter for the readout as well. Works just like an AC ammeter as far as the mechanics go.
 
Re: Electrical Conductivity Test

I've not tried this, but has anyone ever considered a simple paralled bank of ordinary car batteries? Portable, compact, no generator/welder needed, etc.

The auto battery CCA rating spec is for 30sec at stated Amps without dropping below ~7V, so at only 150A, I'd guess 3 or 4 of them would hold up for at least 5 minutes before needing recharge.
 
Re: Electrical Conductivity Test

The piping systems I've seen go in have bonding straps that are connected at each joint in the pipe. The joints are not conductive in themselves.

My question is: In the past, municipal metal water pipe systems have, on occasion, frozen, when the frost got too far down in the ground. Thawing, on occasion, was done by running enough current through the pipe. Are the contemporary pipe and bonding schemes commonly compatible with this scheme?
 
Re: Electrical Conductivity Test

Originally posted by iwire:
Tony how would you control the current level?
Click to expand...
Some sort of simple load maybe? Rheostat off an old junked plating rectifier. I got a barn full of that sort of gear up in NY. Maybe a fixed length of wire wrapped around a broom handle to make a coil like bulb filamant.
 
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