Am I going to blow myself up with AC power and a surge protector?


AaronW
 

Question for the power experts.  I'd like to start learning how to use my rig but I don't want to fry it or my children in the process.

I have a refractor, cooled cmos camera, OAG with guide camera, electronic focusing system, dew band and a power hub all riding on a Mach2.  Plan is to use a NUC for control and remote into the NUC from my indoor desktop via my home's WiFi network.  So there are only three components that wll connect directly to my home's AC power: 1) the CP5 control unit, 2) the NUC, and 3) the Power Hub (Pegasus Powerbox Advance).  All three of these components live on the pier/scope.

The rig is in my backyard ~15 feet away from the nearest outdoor AC outlet.  I was thinking I would buy a surge protector that has a 25 ft cord and run it from my wall outlet to right under my rig, where the above three components can just plug right into it.  I'm not power savvy and was hoping someone could tell me in advance if I'm going to blow something up or if there's a better way :)

Was thinking a Tripp Lite surge protector such as this: https://www.amazon.com/dp/B000UD3LPI/?tag=thewire06-20&linkCode=xm2&ascsubtag=AwEAAAAAAAAAAgeD

Best,
Aaron
  


ap@CaptivePhotons.com
 

It’s important to understand what you want to protect.


The first thing is people – that’s not with a surge suppressor, but with a GFI protected outlet.  My GUESS is your outlet already is, unless it is an older home.  Find that out first.  Daisy chaining GFI is usually not a good idea, sometimes they then trip needlessly.  If yours is NOT protected, either replace it with a GFI outlet (easy, but get an electrician if in doubt), or get a FGI protected extension.  That makes the world safe for people.

 

The surge protector you show is to protect equipment from lightning surges on the line (or other surges of a transient nature).  While not pointless, since most of us will not set up when there are lightning storms anywhere near, this seems much less interesting.  But they are cheap and do no harm.  The surge protector offers zero protection to humans from line voltage.

 

Finally there’s using three different AC -> DC adapters.  I’m a proponent of grounding all of those together so there are no floating voltages against their ground, because if there are, these tend to flow over other connections not intended to carry significant current, notably USB cables.  This doesn’t make them smoke and is not dangerous generally to people but can cause intermittent connections.  However, especially when they are different voltages (as yours probably are) this can be more difficult to do without some custom wiring. Perhaps those more electronically inclined can comment on whether it is actually important to do.  I do know most people do not bother, at least that I have seen.

 

 

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of AaronW via groups.io
Sent: Saturday, September 25, 2021 6:35 PM
To: main@ap-gto.groups.io
Subject: [ap-gto] Am I going to blow myself up with AC power and a surge protector?

 

Question for the power experts.  I'd like to start learning how to use my rig but I don't want to fry it or my children in the process.

I have a refractor, cooled cmos camera, OAG with guide camera, electronic focusing system, dew band and a power hub all riding on a Mach2.  Plan is to use a NUC for control and remote into the NUC from my indoor desktop via my home's WiFi network.  So there are only three components that wll connect directly to my home's AC power: 1) the CP5 control unit, 2) the NUC, and 3) the Power Hub (Pegasus Powerbox Advance).  All three of these components live on the pier/scope.

The rig is in my backyard ~15 feet away from the nearest outdoor AC outlet.  I was thinking I would buy a surge protector that has a 25 ft cord and run it from my wall outlet to right under my rig, where the above three components can just plug right into it.  I'm not power savvy and was hoping someone could tell me in advance if I'm going to blow something up or if there's a better way :)

Was thinking a Tripp Lite surge protector such as this: https://www.amazon.com/dp/B000UD3LPI/?tag=thewire06-20&linkCode=xm2&ascsubtag=AwEAAAAAAAAAAgeD

Best,
Aaron
  


M. Collins
 

On Sat, Sep 25, 2021 at 03:46 PM, ap@... wrote:

Finally there’s using three different AC -> DC adapters.  I’m a proponent of grounding all of those together so there are no floating voltages against their ground, because if there are, these tend to flow over other connections not intended to carry significant current, notably USB cables. 

  In general, it's not necessary to do more than connect your AC adapters into outlets which are closely coupled, as on a power strip. All AC adapters with two-prong plugs, and most with three prong plugs provide isolation between the DC output and the contacts in an AC outlet. If you use a power strip near the telescope and plug all of the adapters into it, you should have no problems at all. Even if you run an Ethernet cable back into your house, there's little risk of problems because the connections are transformer coupled on each end (meaning that there's no direct path for current to flow from the Ethernet cable to the electronics on either end). USB is a little different since it relies upon current flow at both ends of the cable, so you may not want to run that between your office and telescope, however connections between cameras, filter wheels, computers, etc., at the telescope should not present any issues.

  The recommendation to ensure that you have GFCI protection for any line voltage used outdoors is a good one. An inexpensive ground fault detector is a worthwhile tool for any homeowner. These provide a button that allows a small current to pass between line voltage and ground, which will trip a GFCI if there is one in the circuit. If you plug the tester into an outdoor outlet and the lights on the tester don't go off as soon as the test button is pressed, either the existing GFCI has failed or there wasn't one to begin with. That's not a good thing.

  In many houses, the GFCI protecting outdoor outlets is installed in one of the bathrooms. If you have a GFCI in a bathroom, you can plug a lamp into an outdoor outlet then press the test button the GFCI. If the lamp goes off, the outdoor circuit is properly protected.


AaronW
 

Thanks, all.  Very helpful.  I believe my outdoor outlet is already GFCI protected but will perform a test to confirm before plugging anything in.

Best,
Aaron

On Sat, Sep 25, 2021 at 4:27 PM M. Collins <aegle_observatory@...> wrote:
On Sat, Sep 25, 2021 at 03:46 PM, ap@... wrote:

Finally there’s using three different AC -> DC adapters.  I’m a proponent of grounding all of those together so there are no floating voltages against their ground, because if there are, these tend to flow over other connections not intended to carry significant current, notably USB cables. 

  In general, it's not necessary to do more than connect your AC adapters into outlets which are closely coupled, as on a power strip. All AC adapters with two-prong plugs, and most with three prong plugs provide isolation between the DC output and the contacts in an AC outlet. If you use a power strip near the telescope and plug all of the adapters into it, you should have no problems at all. Even if you run an Ethernet cable back into your house, there's little risk of problems because the connections are transformer coupled on each end (meaning that there's no direct path for current to flow from the Ethernet cable to the electronics on either end). USB is a little different since it relies upon current flow at both ends of the cable, so you may not want to run that between your office and telescope, however connections between cameras, filter wheels, computers, etc., at the telescope should not present any issues.

  The recommendation to ensure that you have GFCI protection for any line voltage used outdoors is a good one. An inexpensive ground fault detector is a worthwhile tool for any homeowner. These provide a button that allows a small current to pass between line voltage and ground, which will trip a GFCI if there is one in the circuit. If you plug the tester into an outdoor outlet and the lights on the tester don't go off as soon as the test button is pressed, either the existing GFCI has failed or there wasn't one to begin with. That's not a good thing.

  In many houses, the GFCI protecting outdoor outlets is installed in one of the bathrooms. If you have a GFCI in a bathroom, you can plug a lamp into an outdoor outlet then press the test button the GFCI. If the lamp goes off, the outdoor circuit is properly protected.