Troubleshooting Question

[JFletcher]

Got a call end of yesterday for 3 rooms w/o power at a hotel. By their room numbers, they are all on top of one another. I'm presuming they were initially wired in a riser setup using a common conduit for the home runs.

Scooted by for a quick moment to take a look. All 3 1p 20A breakers were tripped in rooms 408, 508, and 608 and immediately trip back when reset. My thought is that something shorted in the common (riser) conduit taking out everything. I didnt have time to investigate further and asked maintenance to move all of the stuff out of the way of the panels and wire gutters below.

Aside from unlanding the ungrounded conductors from the breakers in question and testing continuity between them (should be none, melted together wire would show continuity), what/where else might I look for problems? This place was built ~40 years ago. Is there any failure point that would be more likely than another, say the j-box, receptacle or light switch where they first come up in the riser? I'm thinking that all 3 circuits failed in the same place...why they might have failed is another matter.

 

[JFletcher]

Any thoughts? If there are 3 circuits melted together, I will be extra careful checking voltages and what not; on a regular branch circuit, securing power to a breaker should kill that circuit completely. If there is a line(s) to line(s) fault, shutting off one breaker would still leave those wires energized.

 

[growler]

Your logic sounds good to me. Is this one complete 3 wire circuit, 3 hots and 1 neutral?

I don't know how these hotel rooms are wired but I know that some use a junction box in the bathroom under the vanity others junction in the kitchen ( extended stay) below cabinets.

If you can find the common point in the first room it should be easy to figure out what's happened. But who knows it may branch off in the hallway.

Good hunting.

 

[JFletcher]

Your logic sounds good to me. Is this one complete 3 wire circuit, 3 hots and 1 neutral?

I don't know how these hotel rooms are wired but I know that some use a junction box in the bathroom under the vanity others junction in the kitchen ( extended stay) below cabinets.

If you can find the common point in the first room it should be easy to figure out what's happened. But who knows it may branch off in the hallway.

Good hunting.

Thank you. I couldn't get the deadfront off yesterday (junk in the way) to check to make sure it isnt a MWBC on 3 1p breakers w/o handle ties. The hallway drop ceiling is a good place to check too - hopefully the boxes are marked - the original panel schedule was badly incomplete, now obsolete, and no new schedule has been made. Will note what I find later on. Any chance of finding a set of electrical drawings on site on a 40+ year old hotel?

I'm going to bring my telecom toners and probes to try to trace it as well - as long as the circuits are off I should be gtg there.

 

[Jraef]

... Junk in the way...

Some education of their staff on code requirements for electrical rooms seems in order. Point out to them that a surprise visit from a fire marshal could result in their having to empty the hotel immediately. I've seen it happen in Vegas, not good for business. Even if it's only for an hour or so, people who are inconvenienced blast that stuff out on social media now and it can kill a business.

 

[JFletcher]

Space in front of panels was cleaned by them.. how long it stays that way is anyone's guess.

Found the culprit, a knot of melted wiring in a 1st floor jbox. The conduit fill was impossibly tight. They rent those rooms to exchange students, four to a room sometimes! Most of their PTACs are broken, so they installed window units which ofc run off of the branch circuits for the rooms. With the overfilled conduit and a lot of amps flowing, I guess a splice failed (overheated) that wiped out everything in the box. Repairing it all isnt going to be much fun but at least I've found the problem. J-box was on an exterior wall near the PTAC.

 

[Little Bill]

Space in front of panels was cleaned by them.. how long it stays that way is anyone's guess.

Found the culprit, a knot of melted wiring in a 1st floor jbox. The conduit fill was impossibly tight. They rent those rooms to exchange students, four to a room sometimes! Most of their PTACs are broken, so they installed window units which ofc run off of the branch circuits for the rooms. With the overfilled conduit and a lot of amps flowing, I guess a splice failed (overheated) that wiped out everything in the box. Repairing it all isnt going to be much fun but at least I've found the problem. J-box was on an exterior wall near the PTAC.

PTAC?

I hope you have better luck than I had with an older hotel. I was called to check out a room where several switches and receptacles weren't working. I had no idea how this was wired so I had to tear most everything apart and start tracing. Of course the room was on a 3rd floor and far away from where I had to enter. I made several trips to my van to get things, which ate up a lot of time.

To shorten the story, the maintenance man was there and told me about some of the things and where the breakers were. Most of what I found was bad/miswired items such as 3-way switches. Pretty sure the maintenance man was the culprit on the miswiring! Anyway when I finished, I told the owner (lady) what I found and collected the check. She asked what my rates were and I explained them to her. Took my check and left.

A couple of days later I get a call from the owner asking why my bill was so high. I told her that I had already explained my rates and what the charges were for. She said her maintenance man told her that I was finished when he left and I shouldn't have that much time billed for. Well when he left, I had found the problem(s) but had not put everything back together, not carried any of my tools out. I explained that to her and she just said she couldn't afford me!

I think the maintenance guy was trying to cover up HIS miswiring and I think the owner thought she should pay me the "low wages" she obviously was paying her maintenance guy.

Sorry I went off topic with that. My initial point was it can be hard to troubleshoot these old hotels (or any building) without knowing what and how things were wired.

OP, glad you found the problem. Hope your experience was better than mine!

 

[JFletcher]

PTAC?

I hope you have better luck than I had with an older hotel. I was called to check out a room where several switches and receptacles weren't working. I had no idea how this was wired so I had to tear most everything apart and start tracing. Of course the room was on a 3rd floor and far away from where I had to enter. I made several trips to my van to get things, which ate up a lot of time.

To shorten the story, the maintenance man was there and told me about some of the things and where the breakers were. Most of what I found was bad/miswired items such as 3-way switches. Pretty sure the maintenance man was the culprit on the miswiring! Anyway when I finished, I told the owner (lady) what I found and collected the check. She asked what my rates were and I explained them to her. Took my check and left.

A couple of days later I get a call from the owner asking why my bill was so high. I told her that I had already explained my rates and what the charges were for. She said her maintenance man told her that I was finished when he left and I shouldn't have that much time billed for. Well when he left, I had found the problem(s) but had not put everything back together, not carried any of my tools out. I explained that to her and she just said she couldn't afford me!

I think the maintenance guy was trying to cover up HIS miswiring and I think the owner thought she should pay me the "low wages" she obviously was paying her maintenance guy.

Sorry I went off topic with that. My initial point was it can be hard to troubleshoot these old hotels (or any building) without knowing what and how things were wired.

OP, glad you found the problem. Hope your experience was better than mine!

Package Terminal Air Conditioner. The AC/heat units in the rooms that sit in a wall sleeve.

Hotels/motels are only okay if the original wiring hasnt been screwed with. The one I used to do maintenance at, they asked me about the electrical. I told them I could work 12 hour days, 6 days a week, 50 weeks a year for five years and I *might*be able to fix all of the wiring problems. And it was that bad....

 

[growler]

Pretty sure the maintenance man was the culprit on the miswiring!


I think the maintenance guy was trying to cover up HIS miswiring and I think the owner thought she should pay me the "low wages" she obviously was paying her maintenance guy.

Working as maintenance in one of the older hotels or motels is some of the worst paying jobs a person can get. That's why they never get anyone even half way qualified to do electrical or much of any thing else. They are often paid much less than an electrician's helper for construction.

 

[cowboyjwc]

Thank you. I couldn't get the deadfront off yesterday (junk in the way) to check to make sure it isnt a MWBC on 3 1p breakers w/o handle ties. The hallway drop ceiling is a good place to check too - hopefully the boxes are marked - the original panel schedule was badly incomplete, now obsolete, and no new schedule has been made. Will note what I find later on. Any chance of finding a set of electrical drawings on site on a 40+ year old hotel?

I'm going to bring my telecom toners and probes to try to trace it as well - as long as the circuits are off I should be gtg there.

We're required to keep commercial plans for ever and always, so you might check with your local building department.

 

[Coppersmith]

Took my check and left.

A couple of days later .... she just said she couldn't afford me!

I guess it's a good thing you already had her check. Hope you cashed it fast. :happyyes: