My understanding of GFCI's is they have a current transformer in them that measures the incoming amp and outgoing amps based on the neutral load. I've seen a few hot tubs that do not have any neutral loads and they say in the manual no neutral required. does a GFCI still provide the protection, and how does the CT measure the amps that would leak if it needed to trip.
gfci breaker protection on hot-tubs
- Thread starter J.J.
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al hildenbrand
Senior Member
- Location
- Minnesota
- Occupation
- Electrical Contractor, Electrical Consultant, Electrical Engineer
Welcome to the Forum J.J.
Two things:
Two things:
- Even though the two pole GFCI breaker is supplying a two wire 240 Volt (only) load, the line side of the breaker must have a neutral, because the electronics of the breaker require the neutral to work.
- In normal operating conditions, the current going out on one hot leg equals exactly the current coming back through the current transformer in the GFCI breaker. The magnetic field around each wire is equal and opposite to the other, and, at any instant, the two magnetic fields cancel each other out. The current transformer has no magnetic field entering it, so nothing happens. When some current "leaks", that is, it doesn't return through the GFCI, then the current out is different than the current back, the magnetic fields created by each current don't quite cancel, and the current transformer has a magnetic field in it that gives an output on the secondary windings connected to the GFCI electronics. When the electronics see a strong enough output from the current transformer, the GFCI trips. This is true whether there are two or three (or more) current carrying conductors passing through the current transformer.
thanks for the reply. my only question is this. If you have a hot tub just like this, is there no way to get gfci protection for the unit. AND is it CODE to put a standard breaker. ex. what happens if someone DOES get shocked, is there no way to provide protection from deadly shock.
g@friendly
Member
- Location
- NJ
It was answered in post #2J.J. said:
I will try to make it easier I had a hard time with this a long way back. The 50 2pole breaker comes with a neutral for the line side.
The breaker reads leakage from ground to hot in the tub and wham breaker trips. It dosn't need a neutral for return. but you still must terminate the neutral at the neutral not the ground in a sub panel.
welcome to the form.
al hildenbrand
Senior Member
- Location
- Minnesota
- Occupation
- Electrical Contractor, Electrical Consultant, Electrical Engineer
J.J.
If the hottub is straight 240 V (no neutral), and the branch circuit supplying the tub is two hots and the equipment ground (no neutral), the the GFCI breaker has to go back at the beginning of the branch circuit where (presumably) there is a neutral.
Look at this Siemens diagram:
Note that the GFCI doesn't watch the Equipment Ground at all.
Also, when the tub has no neutral, the GFCI doesn't watch the neutral. . . just, and only, the two hots. There currents have to be equal and cancel each other out, or else, the GFCI will trip (at 5 milliamps unbalance between the two hots).
The GFCI breaker has its own white wire (neutral) which must be connected to the panel neutral (that's the panel its mounted in). When there is no LOAD neutral, the only reason the GFCI breaker neutral must be connected to the panel is to provide the 120 volts for the GFCI electronics (the little IC and the solenoid that trips the GFCI).
If the hottub is straight 240 V (no neutral), and the branch circuit supplying the tub is two hots and the equipment ground (no neutral), the the GFCI breaker has to go back at the beginning of the branch circuit where (presumably) there is a neutral.
Look at this Siemens diagram:
Note that the GFCI doesn't watch the Equipment Ground at all.
Also, when the tub has no neutral, the GFCI doesn't watch the neutral. . . just, and only, the two hots. There currents have to be equal and cancel each other out, or else, the GFCI will trip (at 5 milliamps unbalance between the two hots).
The GFCI breaker has its own white wire (neutral) which must be connected to the panel neutral (that's the panel its mounted in). When there is no LOAD neutral, the only reason the GFCI breaker neutral must be connected to the panel is to provide the 120 volts for the GFCI electronics (the little IC and the solenoid that trips the GFCI).
barbeer
Senior Member
- Location
- Pinellas County, FL
celtic said:
My VitaSpa does not require a GFCI breaker feed it. Actually there is a form of GFCI protection inherent to the control panel, kind of like a spa pack box if you have ever seen one of those.
Nevertheless, It is fed by a 2p 50 GFCI breaker without the load neutral installed.
:-?barbeer said:
http://www.vitaspa.com/vita_spa_customers/Owners%20Manual/electrical%20requirements.asp
(for L700 + L100 series)
http://www.vitaspa.com/vita_spa_customers/Owners%20Manual/u100electrical%20requirements.asp
(for U100 series)
However...
http://www.vitaspa.com/vita_spa_customers/Owners%20Manual/LD15perfect%20site.asp
(for LD15 series)
Interesting.
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