Elevator with DC power and AC controls requiring one disconnect?

Status
Not open for further replies.

kaichosan

Member
San Francisco, CA location.

An the old elevator with DC power had the AC controls updated. The work was later tagged by the Elevator Inspector for non-compliance. I understand the inspector requires one disconnect for both the 250 VDC power and the 120 VAC control.

Here is the tagged note:
"The conditions in need of correction are noted below, The numbers following the listed items refer to the sections of the California Code of Regulations (Title 8), or the Labor Code (L.C.) of the State of California.

1.) The elevator disconnecting means shall be provided a single means for disconnecting all
ungrounded main power supply conductors for each unit. 620-51"


Questions:
1. Is it not sufficient to have two disconnects next to each other (one for power, and another for AC control)?

2. If not, anybody know of one disconnect to handle both the 205 VDC power as well as 120 VAC controls?

3. Elevator maintenance suggested using existing DC power to run an inverter to get the 120 VAC for control. I'm not sure about inrush currents affecting inverters (1500W).

Thank you in advance, folks!
 

mgookin

Senior Member
Location
Fort Myers, FL
San Francisco, CA location.

An the old elevator with DC power had the AC controls updated. The work was later tagged by the Elevator Inspector for non-compliance. I understand the inspector requires one disconnect for both the 250 VDC power and the 120 VAC control.

Here is the tagged note:
"The conditions in need of correction are noted below, The numbers following the listed items refer to the sections of the California Code of Regulations (Title 8), or the Labor Code (L.C.) of the State of California.

1.) The elevator disconnecting means shall be provided a single means for disconnecting all
ungrounded main power supply conductors for each unit. 620-51"


Questions:
1. Is it not sufficient to have two disconnects next to each other (one for power, and another for AC control)?

2. If not, anybody know of one disconnect to handle both the 205 VDC power as well as 120 VAC controls?

3. Elevator maintenance suggested using existing DC power to run an inverter to get the 120 VAC for control. I'm not sure about inrush currents affecting inverters (1500W).

Thank you in advance, folks!

Answers:
1. Apparently not as long as the inspector wrote the requirement verbatim.
2. You only provide voltage. Amperage will need to be known.
Two options are:
A. A multi-pole disconnect which is rated to handle everything you need to disconnect.
B. A single pole disconnect which is coupled to NO magnetically held relays which remove power to the circuits upon opening the disconnect.
3. ?

There are probably other options available but those two come to mind.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
There may be cheaper options, but I happen to know off the top of my head that the Square D HU36xRB series is rated for both AC and DC and has 3 poles in case your DC is ungrounded. But not knowing your amperage requirements I don't know if the series goes high enough.
 

kaichosan

Member
Thanks fellows:

I contacted Eaton for a single fused disconnect that will disconnect the 250VDC 50A motor ungrounded and also disconnect the 120VAC controls. The controls was just recently upgraded by an elevator controls contractor; but failed the inspection. I prefer this simpler solution.
 
Status
Not open for further replies.
Top