Low voltage

[DnL]

Is this normal? My volt meter reads good voltage (in the green) at the source outlet and inside the RV until I turn on a space heater. With the heater on, the meter drops to the low range.


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[drc343]

What is your good voltage and your low range voltage numbers?

[stevejahr]

A voltage drop typically indicates that the circuit cannot supply the power being drawn from that circuit. Depending on degree operating in this manner can trip circuit breakers (at best) and overheat wiring potentially leading to a fire (at worst). Some devices can be damaged from operating at low voltage for too long, but a heater is not likely a problem here.

Most small heaters are 1500 watts, which is a significant amount for a single device but not overly taxing for a normal 15A household circuit/wiring. Normally the circuit breakers are specified to protect the circuit from overloads. If you are not tripping the breaker then you probably have either a bad connection in the electrical system or a bad supply. Check plugs and connection points for heat indicating a poor connection.

[Bluepill]

You can also try another outlet and see if there is less of a drop. If so, the one that reads low has a poor connection or undersized/damaged wiring.

[VinceU]

Not sure if your rig is a 30 or 50 2 phase unit. Either way one 15 amp load should not cause a voltage drop. Start withe the shore power connection, plug and recep. If possible measure the voltage at the plug while under load. Check the the main breaker in the RV power panel. If at home measure the power bus bars voltage and breaker rating. Somewhere along the line a poor connection or bad breaker is causing the drop


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[Flybob]

What else is running. With the heater on (probably 15A ) the total load could be just under 30A. If the contacts in the pedestal are dirty or damaged from previous overloads or being plugged in and unplugged under heavy load, you will see voltage drop. Also sounds like you need to get a good digital meter and check again, depending on who made and calibrated the one you have, low could be bad or just less than optimal.

[Herk7769]

As Flybob said, this could be a campground issue.

Low campground voltage is not just a "peak of summer" issue, but with everyone running space heaters (in some cases multiple ones) aluminum supply wires can be over tasked reducing delivered voltage.

[bob caldwell]

Nice pic..

[DnL]

Thanks to all for the replies. I'll do some more checking today (after church and football) and see what I can find. Again, thanks for all the input.


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[DaveSchwartz]

Hope you didn't leave the heater plugged in while you went to church and football!

[Herk7769]

Originally Posted by bob caldwell

Nice pic..

I have found that a picture (or valid source) is worth 1000 assertions ...

[bob caldwell]

That is so true......easier to look than read

[jeff64]

If you are running your space heater on the 1500 watt setting, run at the 750 watt setting. Feel the plug end at the outlet, is it warm to the touch? Feel the cord where it goes into the post outlet, if warm, look at the plug and terminals, do you see any evidence of plastic deformation which is a pretty good indicator you need a new plug end. Are you using the dogbone 30A to 15A adaptors? Same holds true, they can be damaged by overcurrent draw too

[elind]

Is the electric water running with the heater?

[keith_h]

Originally Posted by Herk7769

As Flybob said, this could be a campground issue.

Low campground voltage is not just a "peak of summer" issue, but with everyone running space heaters (in some cases multiple ones) aluminum supply wires can be over tasked reducing delivered voltage.

That picture makes a lot more sense than some of the stuff my old instructors used to explain how it worked.

[Bluepill]

I have always taught basic electricity with a plumbing analogy, but I wish I had thought of that diagram.

And the classic ohms calculator triangle is a great tool.

[bubbles]

Actually, it's E/I/R.

[VinceU]

Originally Posted by bubbles

Actually, it's E/I/R.

Truism- it stands for "electromotive force", hardly used in industry but Ohms isn't around anymore! Voltage usage more practical term.


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[youroo]

Originally Posted by Bluepill

I have always taught basic electricity with a plumbing analogy, but I wish I had thought of that diagram.

And the classic ohms calculator triangle is a great tool.

I see this a Lot,but on these Forum's it's (I RV)! Youroo!!

[RamblerGuy]

There is always voltage drop when current flows through a wire. A two to four volt drop is okay on a 15 amp circuit with a 12 amp load. You shouldn't be worried about a fire in this case. The 15 amp breaker will protect the circuit. Even if you had really low voltage, such as 100 volts, it wouldn't case a problem with a resistive load such as an electric heater. You'd just have less current and would get less heat. Low voltage is death on a motor load such as your A/C and on some electronics.

What are you plugged in to? A 15 or 20 amp receptacle? Are you using an extension cord? What length and wire gauge? How many feet of wire feed the receptacle from the breaker? Any of these could be responsible for some of the voltage drop.

At home I have a 30 amp receptacle, use a 50 foot 10 AWG extension cord and, of course, the coach's 30 foot 10 AWG cable and get about a 4 volt drop when I use an electric heater or the electric water heater.