FAQ
TL;DR: Use at least 1.5× conduit-to-cable internal diameter; "minimum diameter ... not be less than 1.5 times." Choose clearance for pulling and future replacement; peszel is flame-retardant, not "self-extinguishing." [Elektroda, kkas12, post #18276044]
Why it matters: This helps DIYers and electricians pick peszel sizes for YDYp floor runs that stay serviceable and safe.
Quick Facts
- For YDYp 3x2.5 laid in a floor, peszel fi 22/18 is recommended. [Elektroda, kozi966, post #18275979]
- A practical rule: internal conduit diameter ≥ 1.5× the cable diameter. [Elektroda, kkas12, post #18276044]
- “It is designed to fit, but not tight,” to allow future replacement. [Elektroda, Anonymous, post #18275908]
- Peszel marketed as “self‑extinguishing” is actually flame‑retardant. [Elektroda, kkas12, post #18276044]
- Round 5x2.5 can use a smaller conduit than a flat cable of the same size. [Elektroda, Shadowix, post #18276388]
What conduit size should I use for YDYp 3x2.5 laid in the floor?
Use peszel fi 22/18. This size was recommended in the thread for YDYp 3x2.5. It gives working clearance for pulling and later replacement. [Elektroda, kozi966, post #18275979]
Is the “conduit must be 3× thicker than the cable” rule real?
No. “It is designed to fit, but not tight.” Prioritize clearance so you can replace the cable in the future. Avoid arbitrary multipliers without context. [Elektroda, Anonymous, post #18275908]
Is a 20/14 peszel too tight for YDYp 3x2.5?
Avoid tight fits. If a test pull binds, step up a size. “Use one that you can easily stretch on the cable.” Tight fits block pulls and replacement. [Elektroda, kkas12, post #18276044]
How do I size conduit if I only know the cable diameter?
Apply the 1.5× rule. Let D (internal conduit) be at least 1.5 times di (cable diameter). This ensures clearance for pulling and replacement. [Elektroda, kkas12, post #18276044]
Should I use rigid or flexible conduit for floor runs?
Both rigid and flexible conduits exist for this purpose. Use purpose-made materials with defined diameters. Do not skimp on conduit cross-sections. [Elektroda, kkas12, post #18276064]
Can I run YDYp 5x2.5 in a smaller conduit if the cable is round?
Yes. Choose a round 5x2.5 cable when possible. A round cable lets you use a smaller conduit than a flat one, easing pulls. [Elektroda, Shadowix, post #18276388]
How do I fix peszel to the floor before the screed?
Use plumber-style clamps or floor hooks to secure the runs. Double clamps help keep pairs aligned. This stabilizes routes before pouring the screed. [Elektroda, kkas12, post #18276171]
Is laying conduits on the floor a good practice?
It’s a last resort. “Laying cables on the floor is a last resort and I avoid it like fire.” Prefer walls or ceilings when possible. [Elektroda, kkas12, post #18276171]
How do I avoid twisting and wedging when pulling cable?
Size the conduit correctly and pre-pull the cable through the peszel. “There is no other option.” Proper diameter prevents twisting and wedging. [Elektroda, kkas12, post #18276553]
What does “self‑extinguishing” peszel really mean?
Expect flame retardancy, not true self‑extinguishing behavior. The conduit slows flame spread but does not extinguish itself. Choose flame‑retardant peszel. [Elektroda, kkas12, post #18276044]
Will I be able to replace the cable later?
Only if the conduit reaches the box and is fully embedded on all sides. Otherwise, “forget about a possible replacement.” Plan continuity end-to-end. [Elektroda, kkas12, post #18276044]
How should I sequence the installation for a smooth pull?
- Pull the cable into the conduit first.
- Check the route for snags and tight bends.
- Lay the assembly on the floor and fix it with clamps.
This order minimizes jams and kinks. [Elektroda, kkas12, post #18276553]
Does conduit size impact heat dissipation here?
The guidance focuses on mechanical clearance and replaceability. Size using the 1.5× internal diameter rule. Avoid tight fits that hinder movement and replacement. [Elektroda, kkas12, post #18276044]
