electronic door lock

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jetlag

Senior Member
My son in law is a licensed lock smith . He had 3 questions for me but I didnt know the answers about electronic door locks

1 - The locks are 12/24 volt dc 300/150 ma , the lock mfg doesnt sell or recommend wire to use from the remote located transformer to the lock, what is the best to use .
2 - He is also wondering if he is in violation for runing the low voltage cable to the transformer mounted above the ceiling without having a low voltage license
3 - The transformer is plug and cord connected and has to have a 120 v circuit ran for the receipt . If a licensed electrician does that is the low voltage work also allowed under the electricians class 2 license .
 

macmikeman

Senior Member
I spent 5 years on a contract installing door lock systems at a large facility so here goes.

1. I used 18-2 solid for door strike type locks

2. Check what local laws are enforced regarding this. Your local AHJ is the one to ask about that.

3. Most likely allowed. Again, this would be local laws that cover this.


You mentioned the transformers would be located above the ceiling, and are plug in type. Watch out for that, that means you are going to be putting a receptacle outlet up where you cannot plug a cord into it..
 

nhfire77

Senior Member
Location
NH
1- The minimum should be 18 gauge. Voltage drop should be considered. Also check with the spec sheet, t normally has the minimum. If the transformer is a wall wart with direct wire to the secondary those can go above a drop ceiling.

2-depends of the state/AHJ.

3-depends of the state/AHJ.
 
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jetlag

Senior Member
1- The minimum should be 18 gauge. Voltage drop should be considered. Also check with the spec sheet, t normally has the minimum. If the transformer is a wall wart with direct wire to the secondary those can go above a drop ceiling.

2-depends of the state/AHJ.

3-depends of the state/AHJ.

The one he is doing now is a drop ceiling . The state is georgia , does any one know if a locksmith can run the low voltage to the lock, and or ,if a license electrician can do it , neither of which have a low voltage license . I am asking as far as the NEC and state is concerned , not the AHJ .
 
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Jim W in Tampa

Senior Member
Location
Tampa Florida
The license issue will be a state and local issue
The transformer is NEC and if above ceiling can not have a cord. If transformer is the plug type 1 piece then its ok.
Personally I would think he can not do any electrical work but check with AHJ.
 

ceb58

Senior Member
Location
Raeford, NC
The one he is doing now is a drop ceiling . The state is georgia , does any one know if a locksmith can run the low voltage to the lock, and or ,if a license electrician can do it , neither of which have a low voltage license . I am asking as far as the NEC and state is concerned , not the AHJ .



An Electrical Contractor license allows for the installation, maintenance, alteration, or repair of any electrical equipment, apparatus, control system, or electrical wiring device which is attached to or incorporated into any building or structure including the bidding and contracting for such work. It does not include Low Voltage work.
  • Class 1 - Restricted Electrical Contractor who is limited to single-phase electrical installations, which do not exceed 400 amperes from the service drop or service lateral.
  • Class 2 - Unrestricted Electrical Contractor who is not limited as to the size or amount of work allowed
It appears that the answer is no. Unless the elect. contractor also holds a LV license. The NEC would be silent on this matter as the laws and rules vary from state to state.
 

jetlag

Senior Member
The license issue will be a state and local issue
The transformer is NEC and if above ceiling can not have a cord. If transformer is the plug type 1 piece then its ok.
Personally I would think he can not do any electrical work but check with AHJ.

So you say above the ceiling a 120/24 v tranny must be hardwired to the supply? I thought the cord and plug was allowed over a suspended tile ceiling .
 

jetlag

Senior Member
thanks ceb58

thanks ceb58

It appears that the answer is no. Unless the elect. contractor also holds a LV license. The NEC would be silent on this matter as the laws and rules vary from state to state.

I knew I remembered something about an electrical contractors license does not include low voltage . So Unless Ga has an amendment, neither the electrician or the locksmith can legally run the low voltage to the lock with out a low voltage license. On the ones he has done so far a permit has not been pulled , but he is worried that he needs to obtain a low voltage license and I wasnt sure what to tell him .
 

ceb58

Senior Member
Location
Raeford, NC
Install the transformer plug type and your ok. Just cant have cords above it. The 1 piece jobs should work fine

Jim, is correct you can use the plug in type transformer but not cord and plug 400.8 (2)

I knew I remembered something about an electrical contractors license does not include low voltage . So Unless Ga has an amendment, neither the electrician or the locksmith can legally run the low voltage to the lock with out a low voltage license. On the ones he has done so far a permit has not been pulled , but he is worried that he needs to obtain a low voltage license and I wasnt sure what to tell him .

The cold hard truth is he is breaking the law. He could be putting his locksmith license in jeopardy.
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
The license issue for Ga. i do not know but pretty much can bet his liability insurance will not cover him. Might do thousands of them and no problem but if one goes south he has serious problem.
Have him check into what license he needs, might be good investment.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
The possibility that the suspended ceiling is an air plenum can also have an effect on the type of cable that can be installed.
 

jetlag

Senior Member
The license issue for Ga. i do not know but pretty much can bet his liability insurance will not cover him. Might do thousands of them and no problem but if one goes south he has serious problem.
Have him check into what license he needs, might be good investment.

I am not even sure we are wiring these correctly , the lock opens when no power is supplied to it , it has panic button by the door to break the current for a timed period . The customers want to be able to lock the doors when they count the money with out leaving their work station . To accomplish this I put the 120 v power on three and four way switches so the tranny can be turned on from several locations . Is this a proper way or should a low voltage switch be installed at each location ?
 

acrwc10

Master Code Professional
Location
CA
Occupation
Building inspector
Your fine with a 3way/ 4way the switch is rated UP TO 125 volts. So if you put less then that on it it is fine, as long as the ampere rating is not higher then the switch rating. Just a side note if using a DC transformer it will lower the amp value of the switch from that of AC.
 

jetlag

Senior Member
Thanks augie

Thanks augie

The possibility that the suspended ceiling is an air plenum can also have an effect on the type of cable that can be installed.

He did call the mfg and someone did say they prefered the plenum wire . But I told him I wouldnt use it unless the space was a plenum
 

jetlag

Senior Member
Your fine with a 3way/ 4way the switch is rated UP TO 125 volts. So if you put less then that on it it is fine, as long as the ampere rating is not higher then the switch rating. Just a side note if using a DC transformer it will lower the amp value of the switch from that of AC.

Thats not how it is wired, Im not using the 3 ways for the low voltage , I am using them to switch the 120 volt receptacle to the tranny , when it it on the lock engages . Should I be switching the low voltage instead ? I didnt think regular snap switches were approved for D C. I wired it that way because would be to much voltage drop to run the D C to every switch location .
 
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ceb58

Senior Member
Location
Raeford, NC
I am not even sure we are wiring these correctly , To accomplish this I put the 120 v power on three and four way switches so the tranny can be turned on from several locations .

He did call the mfg and someone did say they prefered the plenum wire . But I told him I wouldnt use it unless the space was a plenum

Thats not how it is wired, Im not using the 3 ways for the low voltage , I am using them to switch the 120 volt receptacle to the tranny , when it it on the lock engages . Should I be switching the low voltage instead ? I didnt think regular snap switches were approved for D C. I wired it that way because would be to much voltage drop to run the D C to every switch location .

Your telling on your self;)
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
best do some thinking if no power means unlocked. They kill power and walk in with guns. Not what i call good security at all
Yes if switching then do it on 120 side
most use power to unlock door
 
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