TVSS installation

Status
Not open for further replies.

ghelec

Member
Location
Texas
I have a customer who wants a TVSS installed and though I have never installed many had always installed them in the meterbase or main panel so all circuits were protected. The problem here is the POCO told him it had to be on a breaker so their system would not be subject to a fault if it malfunctioned. Have any of you experienced this and if so will it work to put it on a breaker like you would a circuit in the house?
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
Some years back I watched a PE give a demonstration of the effects of the lead length on a whole house TVSS. Out of the package, the leads were about 18" long.

Putting the unit in a panel within reach of an open double pole breaker location and the neutral was relatively easy and yet didn't give a response even remotely close to its specs.

Rearranging the panel to open two poles for the TVSS breaker right next to the neutral and mounting the TVSS directly outside the panel at that breaker allowed trimming the leads down from 18" to about 6" and HUGELY improved the performance of the device.
 

acrwc10

Senior Member
I have installed afew tvss and keeping the leads short is key. Putting it on a breaker will not impede its performance,the surge that they are there to catch is so breif it would not trip a standard breaker,it is for high voltages not amperage. There are many good units avalible with many bells and whistles. If this is for home use look into Leviton.The one thing you need to look at is the clamping voltage the lower the better.
 

tom baker

First Chief Moderator
Staff member
I have installed at least 100 Leviton TVSS untits, including several that cost $2,000
With TVSS:
More is better
You get what you pay for
Short lead length on the power is critical, but not on the ground or neutral.
Use a service entrance rated device at the service or best the meter, and then point of use at other locations.
 

sparkie001

Senior Member
acrwc10 said:
I have installed afew tvss and keeping the leads short is key.

I wish more ECs knew this. My spec calls for leads as short as possible with the TVSS nippled into the panelboard. When I went to do the punch list the TVSS was on the other side of the room fed by about 15ft of conduit!
 

genesparky

Member
Location
Kingman Az.
more TVSS stuff

more TVSS stuff

I am currently installing two Leviton units at our facility. I am planning on installing them right at the main disconnect to each buiding (the first switch from the transformer). I have tandem lugs and I am just an offset nipple away on each one. Does anyone see a problem wit this?
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Interesting.

I was out chatting with a customer the other day. They have had several close by lightning strikes that have done some serious damage to DP and process control equipment.

Besides a TVSS at the service panel, does it make sense to put one on sub-panels?

What about lightning arrestors? Are they worth trying?
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
Bob,

Layering the TVSS is quite a reasonable approach.

Adding a lightning arrestor works as well.

As a rule, the lightning arrestor will take a large hit's energy. The lower levels of the spike that make it past the arrestor will be further trimmed down by the whole system TVSS.

TVSS with even lower clamping voltages (but lower joule limits) can be placed right at the most sensitive hardware.

Since you mentioned process control, don't forget to insert TVSS on any of the long signal lines coming into the sensitive hardware.
 

sparkie001

Senior Member
Be sure to compare apples with apples when reviewing TVSS units. Some mfrs use an inflated surge rating PER PHASE rather than PER MODE as required by NEMA LS1 standard.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
al hildenbrand said:
Since you mentioned process control, don't forget to insert TVSS on any of the long signal lines coming into the sensitive hardware.

The existing comm lines have some kind of protector on them. For reasons that are not clear to me, they only installed them on one end of each line. I would have thought it made more sense to put them on both ends.

Do you have any suggestions for protecting ethernet lines? There is some chance we may replace the existing very slow comm lines. I'd like to do fiber but it can get pricey.

How about 4-20mA signals?

I am more interested in brand names/part numbers then generalities.
 

tom baker

First Chief Moderator
Staff member
Leviton makes a plug in module for ethernet, it plugs into a receptacle and has two RJ-45, its a 5350-pt8, wired would be a 3680CT-5

For a control panel, Phoenix, maker of terminal blocks has din rail mounted.

4-20 mA TVSS I've not used. Typically I use a 250 mA fuse in on the + side. In line series protection is certainly a good concept but in the Puget Sound area we see little lighting.
 

Ragin Cajun

Senior Member
Location
Upstate S.C.
I'm in the process of recommenging serious surge suppression with multiple layers for a client. They lost a major press due to a surge. They have a 1200, 2000, and another 2000A service and I will be adding a 3000A service.

Providing protection in layers is certainly the way to go.

The unit at the incoming service will protect them from external problems, but internal plant VFD's will generate their own spikes. That's where a second or third layer is needed. What one spends for prevention is nothing compared to the lost revenue from a prolonged shutdown!

Remember, there are surge suppressors of every flavor, price, and effectiveness. Do you homework looking at specs - in between the lines, too. Even the big names don't fully meet the standards. I have seen units several feet in dimensions not even coming close in effectiveness to a quality unit smaller than a breadbox. The devil's in the guts, or the lack thereof.

Installation is absolutely critical. The shorter the leads, the better! As for instrumentation, telephone, data, etc. you need protection at BOTH ends.

RG
 
Status
Not open for further replies.
Top