Let's do the Twist!: Reducing Inductance In Wire Leads for your Siemens FS140

[@sassankarai550]

Great bit about the often-disturbed bonding to ground.

[@Zippy1415]

Very good video - thanks! When twisting the wires on the FS140, should you twist all four leads together? Twist the two that connect to the breaker separately? Curious what is the best way to twist. Subscribed for the clear, down-to-earth explanations. Keep up the good work 🙂

[@Wigwhom86]

Very helpful! Thank you! Im installing this unit in my panel soon

[@abrelectric]

Awesome!

[@fredguerra4917]

I seen the twist before. Excellent info.

[@recbo]

We may get to being permitted, committed, required to run our own ground to SPD, but for now I wonder about whether Twist theory should best twist white wire or not, and/or twist each hot with a separate white, like DC Twisted Pair POTS/Cat. Electrical engineers will reply, as soon as we talk online in a DC Ethernet context

[@recbo]

So at 7:30, 24" lead with twist yields 600v. Not 36", but 24" is great for side mounting. I am playing wackamole on other electrician spd conversations, where this issue is posed but not resolved. I refer people to here.

[@TheWilferch]

BTW...I reached out to Siemens Tech line on 3/04/24...... ( what a chore...they changed their phone number and I plowed through 4 alternate numbers !!)...and the true tech guy on the last call.....agreed with me that WHERE we place the breaker on the busbar, either close to main breaker or further down....is of little consequence....but agreed with me that the shortest wire length gives value. The unspoken hint was that the buss is a very heavy "gauge" and therefore all CB's act like being in "parallel", so where you place breaker is of little concern. Whereas we are limited to the small-ish 10 AWG ga wire for the connector of the FS 140, and THAT makes a difference. Caveat....seems to contradict Mersen study regarding bus location.

[@poisonfortheweak]

Yeah that’s interesting. It doesn’t say anything about proximity to the main breaker/line feed entry in the docs. Though they are super anal about constantly mentioning to choose the breaker that is closest to the SPD- which could easily be the furthest from the service lines. It seems to indicate what you said, that shorter leads to the SPD is more critical than where it is on the bar. I mean I get the idea- if a surge comes in from the mains… then you want it to be the closest point to that entry so it can immediately shunt it back to neutral/ground before it gets any further. But electricity is fast. By time it hits the top of the bus it has hit it all. The more important thing I would imagine is it would travel the path of least resistance, right? So it’s gonna take the path that is shortest and easiest to complete the circuit. So if it his the bus bar… what path is it going to choose- from the bus bar, through 16” of lead to the SPD and immediately to neutral/ground? Or is it gonna travel through 50’ of Romex across your house and get to the first thing on that line that can complete the circuit? I’m not an expert or an electrician. But that seems to make the most common sense to me.

[@djc8570]

Interior location with flush mounted panel, to keep wires short...how about drill into side of panel and install SPD adjacent to the panel with very short leads directly to breaker nearest service entrance?

[@abrelectric]

Definitely doable. Challenge is protecting the wires as they pass through the stud and the side of the panel, with conduit, nipple etc.

[@anonimous596]

is there a way to test the ground to make sure it is correct? -- aside from looking to see if there is a wire on the ground rod outside by the panel???? is there always a water pipe ground????? AND when we twist, are we twisting all 4 wires together or just the two going to the breaker????? but mostly, how do we non-professionals know the ground is correct? so I guess the whole does it have to be at the top of the panel thing is a whole lot less important than make it as close to the SPD as possible no matter where it lands on the bus (making sure it hits an odd-even slot so it hits both legs)

[@recbo]

We can only test for ground, not quality of ground. If we had a megger, we could not test ground quality apart from utility's third wire which has a white line on it. Visual inspection reveals most ground deficiencies like grounding conductor disconnected and 2 foot ground rod lying on the grass, I think that's more than half, just that obvious.

[@recbo]

...I guess we might disconnect ground wire at bus or rod, meg just the rod or 2 rods. If ground isnt working at a device or box, something should be visible. We have to notice bond at main, all bare wires bonded at boxes. Spot old romex, for which code leaves us alone to judge how to make that work, pretty much, so that we will git er done for safety sake

[@rogerwhiting9310]

I am watching all your videos...and I just bought a 140 surge protector. Looks simple to do. I want to move a metal handy box to make elbow room. Can i run the handy box with a 6 inch black pipe nipple? Its pre cut and much more solid than 3/4 EMT and connectors. I know you cant do a long run in black pipe...and electricians use black iron nipples all the time. Thanks

[@abrelectric]

Technically, you want to use materials that are listed and approved for that application. Will it work? Yes. Wouldn't necessarily pass an inspection. Your call, sir.

[@rogerwhiting9310]

@@abrelectric thanks

[@vica153]

Are there any drawbacks to the models that replace a breaker? QSPD models have max of 65kA and they use up a slot, but they have zero wire length between L1+L2 and only ~3" for neutral. Best case scenario with FS140 8" of wire. More likely 12" or even more if the installer did not worry about minimizing length. So QSPD is 600V and the FS140 is 600V-900V and a more involved external install. Maybe the worry about them overheating and starting fires has people opting for externally mounted SPD. I can drop in 2 QSPD breakers in my panel and be done with this project in 2 minutes. This also has some redundancy and better VPR. How often do these siemens SPD have catastrophic meltdowns?

[@abrelectric]

If the breaker style SPDs have the specs you like, go for it! They are super simple. This is the kind we use most often because the client just wants Code compliance and is not worried about the highest levels of protection.

[@vica153]

@@abrelectric the only difference seems to be capacity, do you want to cut one open and check?

[@mikieboyblue]

Man I wish I knew this before installing mine. They should put this in the instructions. I think the FS says to put the breaker as close to the incoming line on the bus. What impact does it have if you are not (example, what you mentioned about your Eaton and moving the breaker)?

[@abrelectric]

The FS instructions Say to keep the leads as short as possible,putting the SPD as close to the supply breaker as possible. I think the impact simply comes back to the length of the wire leads. I have reached out to Siemens tech support to get their feedback about twisting the wires to reduce the v p r

[@mikieboyblue]

@@abrelectric agree. As short as possible and we know we do what we can there. Mine is about 12" to ground/neutral bar on the terminal closest to the return wire and about 16" to breaker with the breaker being the first breaker after the main (which I thought the instructions recommended). Didn't twist and if I did now I probably wouldn't have enough wire. Wires are running in EMT in wall. I would love to know what you hear and any details on how a wire bend impacts the vpr.

[@poisonfortheweak]

What I find ironic about the twist being a good thing is it completely goes against “short as possible”- as twisting is inherently requiring more wire “length” to achieve the same length after twist… meaning it might take 16” of straight wire to make a 12” twisted wire. And the second point they drive is straight as possible, no bends or curves if at all possible. A twist is just that, albeit a very gradual curving or bending. So it’s funny to me in that way, but they obviously say it in the documentation.

[@abrelectric]

@poisonfortheweak and, because only 2 wires go to the breaker, and the other 2 go to hot and ground, you can only twist for a short distance anyways

[@TheWilferch]

On your graph at timeline 3:42....for the left-most column data....why is VPR 1200 at 30" length....then oddly drops to 1000 at 33" length....and then again is 1200 at 36" length? Seems some numbers got switched. ASIDE.... the FS100 comes with 10 ga leads.....would much of this question go away with 8 ga , if THAT was used by Siemens ? Seems "too big" gauge for a given breaker Amp rating is OK.....but wouldn't be the other way around ( higher breaker Amp rating with smaller wire).

[@Jim-bx7vs]

Does this surge protector require a lightening rod ?

[@abrelectric]

No, it does not. But, how would that work?

[@Jim-bx7vs]

@@abrelectric I have a whole house generator bout 30feet from the house inside a 7x7ft shed and a DuroMax 10,000 watts and grounded to a copper rod 8ft into Earth ,I saw some where on you tube that the surge protector had to be grounded I didn't know, that was my reason for asking.

[@abrelectric]

@Jim-bx7vs by 'grounded' the manufacturer means connected to an equipment grounding conductor that goes back to the service panel.

[@Dead_Aim556]

Does moving the breaker all the way down to the buss bars make difference since it is further away from the other circuits?

[@abrelectric]

Moving the spd breaker closer to where the feeders attach to the main breaker helps the performance.

[@craigdanielski]

@@abrelectric I've read many of your other comments that it doesn't matter where the SPD breakers are installed relative to the main disconnect. The comment above seems to be the most recent on the topic. Did you receive new information from Siemens that changed your mind? Thanks for the clarification and the great content you provide!

[@abrelectric]

@Craig Danielski Interestingly, the Siemens tech support was almost ambivalent. I was asking about twisting the leads, which he said didn't matter in residential. I think it's a good practice to be as close as possible to the main feeders. I wouldn't move all your breakers to get there, though.

[@craigdanielski]

@@abrelectric thanks for clarifying because that’s my exact situation. To mount in first stab after main breaker, I would have to move all of my breakers, install tandems, and punch through the side of my box. The hots and ground lengths would be about 9” and the neutral 30”. If I mounted the SPD breaker at the bottom of the panel, hots and ground are 6”, neutral is 18”.

[@abrelectric]

@@craigdanielski sounds like a win!

[@bluesriderDF]

What is the significance of the A & C designation on the 2 hot wires for the FS140? I couldn't find anything on this.

[@TheWilferch]

I could be wrong but I believe, it's the 2 "legs" on your main panel, each at 110-120V ( to make 220/240V). Agreed....it's odd...as in the panel these 2 legs are labelled A and B.

[@bluesriderDF]

I sent a note to Siemens and they actually called me back. The A and C are just the two legs like you said. They didn't give me a definitive answer for why they use that instead of A and B.

[@mackfisher4487]

A Surge protector strategy, like any other insurance is not foolproof, and the insurance companies always say it's an act of God and we don't cover it. One customer had multiple layers of SPDs when the utility companies 25 KV line fell down on the 12 KV line. The resulting prolonged over voltage was well beyond that of the surge protectors parameters.