Continuity Issue

[Charlie Bob]

I did a hot tub installation yesterday. Went back today to finish thing up.
I got my fluke T5 and check for continuity at Hot Tub GFCI disconnect.
I checked the feeder first (Line side, from panel box.), everuthing OK.
I checked the supply side then, and had:

L1-L2 OK

L1-N , L1-G OK

L2-N 35 Ohms. (Meter beeped)

First thing i thought was that we nicked them wires when we pulled them. I used EMT against a wall from HT disc. and then went to LFNC 3/4" to control box in Tub.

I disconnected the supply line at the Hot Tub control box, and everything was just perfect.
Hooked the wires back up, and again 35 Ohms from L2-N.

I Turned power on and everything is OK, breaker held, and GFCI never tripped.
I can guarantee everything i did from Panel box to hot tub is OK, and double checked.

What do you think there's in the Hot Tub that will make my meter to read 35 Ohms from L2 to N,?

I did the required convertion from 110v to 240v specified by Manufacturer.(which consisted of a little switch being swapped from on to off)

 

[Charlie Bob]

Forgot to say, i did double check my readings with a Fluke T-Pro. same readings.

 

[kwired]

was you checking N-G with the N & G connected at both the supply and the load?

The GFCI breaker (that you most likely are using) has a neutral conductor but may not necessarily have a switch to open the neutral when the breaker is off. If this is the case I am surprised you would not have an even lower resistance. I guess I do not know if GFCI breakers open the neutral I know many receptacles do.

Or you could have measured the resistance through the GFCI control circuitry back to the neutral which is bonded to the equipment ground at the service.

Do your continuity check on the equipment with the supply conductors including neutral and ground disconnected. This will tell you which direction the continuity is coming from.

 

[kwired]

Sorry I read your post again and misunderstood it.

You had 35 ohms from L2 to N.

This means there was a load with a resistance of 35 ohms connected between these conductors.

 

[Charlie Bob]

was you checking N-G with the N & G connected at both the supply and the load?

The GFCI breaker (that you most likely are using) has a neutral conductor but may not necessarily have a switch to open the neutral when the breaker is off. If this is the case I am surprised you would not have an even lower resistance. I guess I do not know if GFCI breakers open the neutral I know many receptacles do.

Or you could have measured the resistance through the GFCI control circuitry back to the neutral which is bonded to the equipment ground at the service.

Do your continuity check on the equipment with the supply conductors including neutral and ground disconnected. This will tell you which direction the continuity is coming from.

The low reading was from L2 to N, at the HT Disc. with the GFCI breaker off.
My guess is that it was reading a load in the HT itself, hooked up beetween L2 and N. (110v load)

 

[mcclary's electrical]

The low reading was from L2 to N, at the HT Disc. with the GFCI breaker off.
My guess is that it was reading a load in the HT itself, hooked up beetween L2 and N. (110v load)

Reading continuity throught the control panel or light

 

[LarryFine]

You had 35 ohms from L2 to N.

This means there was a load with a resistance of 35 ohms connected between these conductors.

And they call me Captain Obvious. :roll: ()

 

[mcclary's electrical]

Sorry I read your post again and misunderstood it.

You had 35 ohms from L2 to N.

This means there was a load with a resistance of 35 ohms connected between these conductors.[/QUOTE]



You have a keen grasp of the obvious, my dear watson

 

[kwired]

Many times the obvious things are the easiest things to overlook.

People have a tendency to think things are more complicated than they are.

Have you ever had a service call because something did not work and when you get there you find it is not plugged in and nothing else is wrong?

 

[LarryFine]

Have you ever had a service call because something did not work and when you get there you find it is not plugged in and nothing else is wrong?

Yeah, just a little while ago. Our local cable company recently went all-digital, so everyone needs a box now. My dad called and said he couldn't get the TV to work after connecting the cable box in line.

To make a ridiculous story short, he hadn't plugged the TV's power cord back in. This was necessary for him to tune the TV to channel 3. It took about 5 minutes of conversation to narrow it down.

At least I didn't have to drive over there. :roll:

 

[big john]

Hooked the wires back up, and again 35 Ohms from L2-N.

Unless there's something fancy going on, that's a 3.4A load. Sounds to me like your'e reading through some hardware in the hot-tub. If the GFCI held, and everything is properly grounded and bonded, I wouldn't sweat it.

But if you wanted you could narrow down the problem by opening L2 at the hot-tub and seeing if the hot-tub wiring shows 35 ohms between line and neutral. That would tell you for sure that this wasn't your doing.

Have you ever had a service call because something did not work and when you get there you find it is not plugged in and nothing else is wrong?

Often enough that whenever I get a call about a light not working, the very first thing I do is replace the lamp.

-John

 

[K8MHZ]

Unless there's something fancy going on, that's a 3.4A load. Sounds to me like your'e reading through some hardware in the hot-tub.

That's 400 watts. At 13 cents a kW hour that's over 35 bucks a month.

Does the OP see a 3.4 amp draw when the unit is connected but still off?

Assuming 'supply side' meant the load side of the disco, a relay coil in the tub may be the source of the unexpected ohms. If so, it would explain why there is only a fraction of an amp (for instance) actually being drawn after being energized.