The Shulchan Aruch (Siman 255) permits lighting a fire before Shabbos provided it is caught enough for the flame to rise on its own (shalheves olah me'eileha), without needing to stoke it or move the logs during Shabbos (the fear shema yechateh v'yanid). If it is not sufficiently alight, one may not benefit from it on Shabbos.
Charcoal and fast-burning fuels require only a minimal lighting, since they consume themselves. For a concrete case, ask your Rav.
Siman 255 sets a simple rule: on Shabbos one benefits only from a fire that is already self-sustaining. The flame must rise on its own (שלהבת עולה מאליה) before the onset of Shabbos; otherwise we fear one might stoke it or move the logs (שמא יחתה ויניד). Charcoal and straw, which burn on their own, need only a minimal lighting. Applied to candles and heating. For a concrete case — ask your Rav.
You light the candles, start the heating, switch on the hotplate — just before the onset of Shabbos. But from what point is that fire "sufficiently lit" so one may benefit from it all Shabbos without touching it? The Shulchan Aruch answers, in Siman 255 of Hilchos Shabbos (Orach Chaim), regarding the wood fire (medurah).
What does the Shulchan Aruch say in Siman 255?
The Mechaber (Rabbi Yosef Karo) opens the siman with the rule of the wood fire:
אֵין עוֹשִׂין מְדוּרָה מֵעֵצִים סָמוּךְ לַחֲשֵׁכָה עַד שֶׁיַּצִּית בָּהֶם הָאוֹר בְּעִנְיָן שֶׁתְּהֵא הַשַּׁלְהֶבֶת עוֹלָה מֵאֵלֶיהָ בְּלִי סִיּוּעַ עֵצִים אֲחֵרִים.
"One does not make a wood fire close to nightfall — except when the fire has caught in it such that the flame rises on its own, without the aid of other logs."
For a single log, the Mechaber specifies that the fire must have caught over the greater part of its thickness and of its circumference. Otherwise, it is forbidden to benefit from it on Shabbos.
The principle: שמא יחתה ויניד
The underlying reason: we fear that in wanting to raise an insufficient fire, one might stoke the embers or move the logs — two acts forbidden on Shabbos. Hence the requirement: to use only a fire that is already stable and self-sustaining before the onset of Shabbos.
Charcoal and fast fuels: a minimal lighting is enough
The siman draws a distinction by fuel. For charcoal (פחמין), seif ב reports a lenient view (יש אומרים):
יֵשׁ אוֹמְרִים שֶׁבְּפֶחָמִין אֲפִילּוּ לֹא אָחַז בָּהֶם הָאוֹר אֶלָּא כָּל שֶׁהוּא — שָׁרֵי, מִפְּנֵי שֶׁהֵם דּוֹלְקִים וְהוֹלְכִים.
"Some say that with charcoal, even if the fire has caught in it only the slightest amount (כל שהוא), it is permitted — because it keeps burning on its own."
Likewise, seif ג places on the lenient side pitch, sulfur, straw and stubble (זפת, גפרית, קש, גבבא): they burn fast and fully, so there is no need to stoke. The criterion "a flame that rises on its own" is met structurally by their very nature.
| Fuel | Requirement | Why |
|---|---|---|
| Wood (עצים) | Flame that rises on its own; single log: greater part of thickness + circumference | Without it, the temptation to stoke / move |
| Charcoal (פחמין) | Minimal lighting (כל שהוא) | It keeps burning on its own |
| Straw, stubble, pitch, sulfur | Minimal lighting | They burn fast and fully |
Modern application: candles, heating, hotplate
- The Shabbos candles: the wick must be caught enough for the flame to be stable before the onset of Shabbos — the very spirit of the siman.
- The heating: a fire or an appliance must be sufficiently lit and set before Shabbos, so that nothing prompts one to stoke or relight.
- The hotplate and electric appliances: the principle of a self-sustaining and stable fire before Shabbos guides the reasoning, even though electricity raises its own questions, treated elsewhere.
Contemporary authorities rely on this framework to discuss our sources of fire and heat — with nuances depending on the type of appliance and the minhag.
This article presents what the source says for the purpose of study. It does not rule on any practical case. To know how to light your fire, your candles or your heating — depending on your community and your situation — ask your Rav.
Frequently asked questions
May you light a fire before Shabbos?
Yes, Siman 255 permits it provided it is caught enough for the flame to rise on its own, without needing to be stoked and without one moving the logs. Otherwise, one may not benefit from it on Shabbos. For a concrete case, ask your Rav.
What is required for candles and heating?
The same principle: the wick of the candles must be sufficiently alight and the heating sufficiently on before Shabbos, so that nothing prompts one to stoke or relight. The details vary by appliance — ask your Rav.
What is the fear שמא יחתה ויניד?
The fear that one might stoke the embers or move the logs to make the flame rise — two acts forbidden on Shabbos. It is the underlying reason of the siman: to use only a fire that is already self-sustaining. For practice, ask your Rav.
Study Siman 255 in depth
Four levels, from beginner to talmid chacham — Hebrew text, translation, pilpul and the shitah of the Admur HaZaken.