The AM Forum

Last week I had a very close call loosing a lot of equipment. My line voltage increased to 148v, and the 240 feed hit 313v. Stayed that way for about 15 minutes. Fortunately I was home and quickly pulled the main breaker and shut the house down. Simultaneously our FD got 4 call for smoke coming out of various devices, within 4 businesses. I called the PD who had no idea what was causing it. I explained and they relayed the info to the FD.

Now, I’ve decided to install some sort of auto shut down on the power feeding the shack if the line voltage exceeds a specific voltage. Anyone have any ideas or suggestions for such a device?

That evening two reps from the local utility company PSEG stopped by to thank me for calling in the incident. He said it was a malfunction of a phase switcher at a local sub station. More interesting, when our PD contacted them they were not aware of any problems.

Products like this
 https://furmanpower.com/product/20a-power-conditioner-with-lights-voltmeter/ (https://furmanpower.com/product/20a-power-conditioner-with-lights-voltmeter/)
Are good at keeping your gear intact.  In my work with portable live sound systems, we used various models in every rack. Besides being decent power strips, the surge protection and over-voltage shutdown have saved gear from generator problems more than a few times. They are not cheap but are worth it.  There’s one in my station’s rack and another on my workbench. as well as in my PA system racks.

Note that there are many brands and models of "surge supressors" that knock down spikes, but many provide no over-voltage protection. Read the specs before spending your money...


Ed

Use Joslyn suppressors on our 480V 3-ph service entrance.

They have <2ns rise time, have caught surges such that it opened the 200A fuse on the 'hot' leg.  They clamp @ 600V.

6 of 'em, each about the size of a pop can.  L to L, & L to Gnd.

Good suppressors are really worth the coin.

73DG